What are the best online resources to prepare for GATE exam - Computer Science?

1) Massachusetts Institute of Technology's http://ocw.mit.edu/index.htm 2) https://www.coursera.org/ 3) http://nptel.iitm.ac.in/ P.S: I'll make additions to the list If I know additional resources. Suggestions are welcome

http://getbook.co/gate has all the online  resources for GATE prep https://www.facebook.com/groups/core.cs/ is a community for GATE preparation and many GATE toppers share their experiences. Here is a sample post on Preparation 1>>Good technical knowledge 2>>Good understanding of Basic Concepts 3>>Ability to apply the knowledge and concepts on variety of  problems To Develop 1 and 2 you will need to read and understand  reference books, to develop 3 you will need to solve the problems. Now question  is from where to get the problems or the MCQs, the answer is  the problems are given at the back of every chapter in the reference  books, you will need to solve those problems,may be not all of them.  Problems reveal lot of truth and clear our misconception and  false convictions. And GATE has certain property that lot of Questions in  it are based on concepts that are revealed in certain problems in  reference books. So its really really important to have a shot at the  problems. DISCRETE MATHEMATICS I started my preparation with discrete maths, and I would recommend  you also to start with this perticular subject because this is the  subject from where Computer Science spreads out. Understanding of this  subject is very important. I used following books: 1>>"Discrete maths and its applications" By Kenneth Rosen This is an excellent book for GATE preps. Lot of problems are given  at the end of every chapter plus answers are also given to odd numbered  exercises. The explaination in this book is really very good and "easy  to understand". This book is must read for GATE preps. 2>>book by Tremblay and Manohar I recommend you to read this book after you have read Rosen’s book.  The contents in this book is hard to comprehend. You need to have your  basics cleared before you attempt this book. This book is also a "must   read". I also have the lecture notes on discrete maths from some prof at  McGuire university the advanced counting and recurrence relation part  is good. ALGORITHMS I recommend to you to read this subject along with Discrete maths or  after you have completed discrete maths. I used only one book for this subject and found that to be more than enough for GATE. 1>>"Introduction to Algorithms" By T.H.Cormen et al. This is "THE" book for Algorithms. The Book is simply brilliant, it  makes you understand every details of Algorithms. So this book is a must  read. Although I did not read the entire thing. Here is the list of  chapters that I had read. If you are interested of course you can read  the entire book. Chapter 1,2,3,4[excluding 4.4],6,7[excluding 7.3],8,10,11[excluding  11.5],12[excluding 12.4],18,22,23,24[excluding 24.4 and 24.5] for  NP-Completeness you can read 34 also. In addition to this book I  strongly recommend you to see the video lectures from MIT. The lectures  are given by Lieserson[who BTW is also one of the authors of CLRS] and Erik demaine. The lectures are absolutely brilliant. You may download them from http://ocw.mit.edu/  DATASTRUCTURES I did not read this subject exclusively. I mostly participated in  discussions in Algorithms and datastructures communities on orkut . That  is i think more than enough. • THEORETICAL COMPUTER SCIENCE I initially tried to decipher Ullman’s book but I found the content  too much for my brain to comprehend. So I switched to "Introduction  toComputer Theory" By Daniel Cohen. The contents in this book are lucid. Also solving or atleast attempting the problems in the exercises is a must. But its really great if you could read Ullman. • DATABASE MANAGEMENT SYSTEMS I used Korth and Navathe for this. Initially I read korth because it  is lucid and then only for normalization i read Navathe. The database  design part in korth is difficult so read this part with utmost  concentration and you may require several readings before you begin to  understand things. OPERATING SYSTEMS Read this from following books: 1>>Operating System Concepts By Galvin et al. 2>>Stallings Attempt problems in Stallings they are very important especially  problems on memory management and virtual memory. In Galvin the theory  on memory management is excellent. • Digital Design Read "Digital Design" By morris mano [period].• COMPUTER ARCHITECTURE Read this from following books 1>>"Computer Architecture" By Morris mano 2>>"Computer Organization" By Zacky,hamacher 3>>"Computer Organization Hardware/Software Interface" By Hennessey and Patterson Read book 1 almost completely then read memory system from book 2 then you can read book 3, I had read only the performance measurement chapter from book 3 as it is not given in any other book and also solve numericals fromexercises they are very very important. I recommend you to read this subject after "Digital Design". • COMPUTER NETWORKS I had read this subject only from forouzan and had read some chapters  from Comer’s book. Attempt the exercises from forouzan they are important. • C programming You read this from "the C programming language" by kernighan and  Ritchie that is more than enough plus spend some time in actually programming in C that is the best way you can learn C. • C++ I dont know C++ much and I did not read anything for C++. Dont be spoiled, you can read C++ complete reference if you wish to. Compiler Design  "People" say Ullman’s book is  excellent so you can read it from Ullman if you believe "People". In the  final phase of your preps "try" to solve GATE papers. The answers for  the GATE papers are not present anywhere but still you should attempt  them anyway. This will give youconfidence that you can actually solve  GATE. You can read all the subjects given here you can skip one or two  if you dont have much time But more important thing is to  "MASTER"atleast 2 or 3 subjects. Also actively participate in  discussions at GATE CS or GATE CS/IT 2009 and Algorithms and  Datastructures community in http://orkut.com/ that helps alot in patching few  loopholes in our concepts and enhancing your problem solving skills. Thats it guys,this much is I think enough to crack GATE. You can ofcourse Device your own methodsand set of books. Just be confident you can do it!  These are few URLs Which I think "might" be helpful 1>>Opencourseware at MIT>>>>OCW

I prepared for GATE exam just for a week and managed to get around 2100 rank in Mechanical. Later on me and 10 of my friends from IIT Jodhpur created an online learning website (www [dot] freedu [dot] in) (http://www.freedu.in/) where any one can prepare for GATE exam. Its absolutely free. It have 1000 of questions in aptitude and reasoning, Finest courses from IIT Professor's (under NPTEL mission) as well. Best thing is you can even try for chapter wise quiz in each stream (Mechanical, Electrical and Computer Science till date... instrumentation will be next) Freedu will keep track of your performance and you will be able compare your score with others. It will give you statistical report of your performance as well. Right now its in beta phase but you will enjoy solving questions online, giving chapter wise quiz. You can also enrol yourself in courses by NPTEL. With freedu its easy for you to keep track of your progress in this courses. https://www.freedu.in/qb/ Check Free Computer Science Question Bank for Free! https://www.freedu.in/quiz/ and Free Mock tests for computer science papers are available here You will get a detailed profile like this which will help you overcome your weak links Check out our awesome Facebook page (https://www.facebook.com/freedu.in) glimpse here Give it a try and do tell us how we can make it better for you. After all we are designing it for you.

There is a wonderful book titled "Multiple Choice Questions (MCQs) in Computer Science by my friend Timothy Williams. It is also a very good reference material for those who are serious about their GATE exam preparation.

As you have mentioned in question GATE is a Entrance Test for admission to PG Courses in premier institutes, then why don't we learn from the professors of premier institute! good idea,no?!Yes, the answer is NPTEL Videos. This has been proven best & authenticated resource available online for free for the preparation. Given the detailed explanation of most of the subjects, one can master by learning from there.http://nptel.ac.in/courses.php Keep in mind that you have to give ample amount of time with absolute focus. Along with that you can join some online test series available by various institutes.But my personal suggestion would be buy (only necessary) books & read them. You will never regret the decision of investing money in Books.

http://www.ankurgupta.net/gate-notes/ This contains notes for gate which are prepared by a student in IISC (Ankur Gupta) 2.http://nptel.ac.in/courses.php?disciplineId=106 This contains Videos for gate which are prepared by IIT professors http://3.http://www.aceenggacademy.com/gate/gate-2015/gate-2015-all-india-online-test-series Enroll for Test Series at Cost of 250/- http://4.https://www.digialm.com/EForms/Mock/Template/index.html?585%40%40181 Finally take mocks and reffer Previous year papers http://nptel.ac.in/gate_paper.php It’s just a suggestive list.Choice is Yours If it is Usefull GoForIt,Sure ull crack GATE. ALL THE BEST

You could find some of the relevant Mathematics, Computer Science and Digital Systems course material over here at: http://www.thelearningpoint.net/ Disclaimer: A small personal project of mine Syllabus for Gate Computer Science ENGINEERING MATHEMATICS    Mathematical Logic: Propositional Logic; First Order Logic.Probability: Conditional Probability; Mean, Median, Mode and Standard Deviation; Random Variables; Distributions; uniform, normal, exponential, Poisson, Binomial. Set Theory & Algebra: Sets; Relations; Functions; Groups; Partial Orders; Lattice; Boolean Algebra. Combinatorics: Permutations; Combinations; Counting; Summation; generating functions; recurrence relations; asymptotics.Graph Theory: Connectivity; spanning trees; Cut vertices & edges; covering; matching; independent sets; Colouring; Planarity; Isomorphism. Linear Algebra: Algebra of matrices, determinants, systems of linear equations, Eigen values and Eigen vectors.Numerical Methods: LU decomposition for systems of linear equations; numerical solutions of non-linear algebraic equations by Secant, Bisection and Newton-Raphson Methods; Numerical integration by trapezoidal and Simpson’s rules. Calculus: Limit, Continuity & differentiability, Mean value Theorems, Theorems of integral calculus, evaluation of definite & improper integrals, Partial derivatives, Total derivatives, maxima & minima. COMPUTER SCIENCE AND INFORMATION TECHNOLOGY Digital Logic: Logic functions, Minimization, Design and synthesis of combinational and sequential circuits; Number representation and computer arithmetic (fixed and floating point). Computer Organization and Architecture: Machine instructions and addressing modes, ALU and data-path, CPU control design, Memory interface, I/O interface (Interrupt and DMA mode), Instruction pipelining, Cache and main memory, Secondary storage. Programming and Data Structures: Programming in C; Functions, Recursion, Parameter passing, Scope, Binding; Abstract data types, Arrays, Stacks, Queues, Linked Lists, Trees, Binary search trees, Binary heaps. Algorithms: Analysis, Asymptotic notation, Notions of space and time complexity, Worst and average case analysis; Design: Greedy approach, Dynamic programming, Divide-and-conquer; Tree and graph traversals, Connected components, Spanning trees, Shortest paths; Hashing, Sorting, Searching. Asymptotic analysis (best, worst, average cases) of time and space, upper and lower bounds, Basic concepts of complexity classes – P, NP, NP-hard, NP-complete. Theory of Computation: Regular languages and finite automata, Context free languages and Push-down automata, Recursively enumerable sets and Turing machines, Undecidability. Compiler Design: Lexical analysis, Parsing, Syntax directed translation, Runtime environments, Intermediate and target code generation, Basics of code optimization.Operating System: Processes, Threads, Inter-process communication, Concurrency, Synchronization, Deadlock, CPU scheduling, Memory management and virtual memory, File systems, I/O systems, Protection and security. Databases: ER-model, Relational model (relational algebra, tuple calculus), Database design (integrity constraints, normal forms), Query languages (SQL), File structures (sequential files, indexing, B and B+ trees), Transactions and concurrency control. Information Systems and Software Engineering: information gathering, requirement and feasibility analysis, data flow diagrams, process specifications, input/output design, process life cycle, planning and managing the project, design, coding, testing, implementation, maintenance. Computer Networks: ISO/OSI stack, LAN technologies (Ethernet, Token ring), Flow and error control techniques, Routing algorithms, Congestion control, TCP/UDP and sockets, IP(v4), Application layer protocols (icmp, dns, smtp, pop, ftp, http); Basic concepts of hubs, switches, gateways, and routers. Network security – basic concepts of public key and private key cryptography, digital signature, firewalls. Web technologies: HTML, XML, basic concepts of client-server computing. You might find a lot of the notes and tutorials and source-code-snippets on our website useful for studying Mathematics, Computer Science, Programming and Digital Systems for the GATE CS Examination. http://...Probability http://www.thelearningpoint.net/home/mathematics/a-basic-introduction-to-probability-part-0 http://www.thelearningpoint.net/home/mathematics/probability---part-1 http://www.thelearningpoint.net/home/mathematics/probability---part-2---a-tutorial-on-probability-distributions http://www.thelearningpoint.net/home/mathematics/probability---part-3---joint-probability-bivariate-normal-distributions-functions-of-random-variable-transformation-of-random-vectors Linear Algebra http://www.thelearningpoint.net/home/mathematics/linear-algebra---matrices-part-i Introduction to Matrices. Theory, definitions. What a Matrix is, order of a matrix, equality of matrices, different kind of matrices: row matrix, column matrix, square matrix, diagonal, identity and triangular matrices. Definitions of Trace, Minor, Cofactors, Adjoint, Inverse, Transpose of a matrix. Addition, subtraction, scalar multiplication, multiplication of matrices. Defining special types of matrices like Symmetric, Skew Symmetric, Idempotent, Involuntary, Nil-potent, Singular, Non-Singular, Unitary matrices. http://www.thelearningpoint.net/home/mathematics/linear-algerba---matrics-part-ii Problems and solved examples based on the sub-topics mentioned above. Some of the problems in this part demonstrate finding the rank, inverse or characteristic equations of matrices. Representing real life problems in matrix form. http://www.thelearningpoint.net/home/mathematics/linear-algebra---determinants Introduction to determinants. Second and third order determinants, minors and co-factors. Properties of determinants and how it remains altered or unaltered based on simple transformations is matrices. Expanding the determinant. Solved problems related to determinants. http://www.thelearningpoint.net/home/mathematics/linear-algebra---simultaneous-equatiosn-in-multiple-variables Representing a system of linear equations in multiple variables in matrix form. Using determinants to solve these systems of equations. Meaning of consistent, homogeneous and non-homogeneous systems of equations. Theorems relating to consistency of systems of equations. Application of Cramer rule. Solved problems demonstrating how to solve linear equations using matrix and determinant related methods. http://www.thelearningpoint.net/home/mathematics/basic-concepts-in-linear-algebra-and-vector-spacesTheory and definitions. Closure, commutative, associative, distributive laws. Defining Vector space, subspaces, linear dependence, dimension and bias. A few introductory problems proving certain sets to be vector spaces. http://www.thelearningpoint.net/home/mathematics/introductory-problems-related-to-vector-spacesProblems demonstrating the concepts introduced in the previous tutorial. Checking or proving something to be a sub-space, demonstrating that something is not a sub-space of something else, verifying linear independence; problems relating to dimension and basis; inverting matrices and echelon matrices. http://www.thelearningpoint.net/home/mathematics/linear-algebra---more-about-vector-spaces Defining and explaining the norm of a vector, inner product, Graham-Schmidt process, co-ordinate vectors, linear transformation and its kernel. Introductory problems related to these. http://www.thelearningpoint.net/home/mathematics/linear-algebra---linear-transformations-operators-and-maps Solved examples and problems related to linear transformation, linear maps and operators and other concepts discussed theoretically in the previous tutorial. http://www.thelearningpoint.net/home/mathematics/linear-algebra---eigenvalues-eigenvectors-and-cayley-hamilton-theorem Eigenvalues, eigenvectors, Cayley Hamilton Theorem http://www.thelearningpoint.net/home/mathematics/linear-algebra---problems-based-on-simultaneous-equations-eigenvalues-eigenvectorsDemonstrating the Crammer rule, using eigenvalue methods to solve vector space problems, verifying Cayley Hamilton Theorem, advanced problems related to systems of equations. Solving a system of differential equations . http://www.thelearningpoint.net/home/mathematics/linear-algebra---a-few-closing-problems Solving a recurrence relation, some more of system of equations. http://...Single Variable Calculus    http://www.thelearningpoint.net/home/mathematics/calculus---introductory-definitions-related-to-functions-limits-and-continuity - Defining the domain and range of a function, the meaning of continuity, limits, left and right hand limits, properties of limits and the "lim" operator; some common limits; defining the L'Hospital rule, intermediate and extreme value theorems. http://www.thelearningpoint.net/home/mathematics/calculus---functions-limits-and-continuity---problem-set-i- - Solved problems demonstrating how to compute the domain and range of functions, drawing the graphs of functions, the mod function, deciding if a function is invertible or not; calculating limits for some elementary examples, solving 0/0 forms, applying L'Hospital rule. http://www.thelearningpoint.net/home/mathematics/calculus---functions-limits-and-continuity---problem-set-ii More advanced cases of evaluating limits, conditions for continuity of functions, common approximations used while evaluating limits for ln ( 1 + x ), sin (x); continuity related problems for more advanced functions than the ones in the first group of problems (in the last tutorial). http://www.thelearningpoint.net/home/mathematics/calculus---functions-limits-and-continuity---problem-set-iii - Problems related to Continuity, intermediate value theorem. http://www.thelearningpoint.net/home/mathematics/calculus---introducing-differentiable-functions-and-differentiation - Theory and definitions introducing differentiability, basic differentiation formulas of common algebraic and trigonometric functions , successive differentiation, Leibnitz Theorem, Rolle's Theorem, Lagrange's Mean Value Theorem, Increasing and decreasing functions, Maxima and Minima; Concavity, convexity and inflexion, implicit differentiation. http://www.thelearningpoint.net/home/mathematics/calculus---differential-calculus---problem-set-i- Examples and solved problems - differentiation of common algebraic, exponential, logarithmic, trigonometric and polynomial functions and terms; problems related to differentiability . http://www.thelearningpoint.net/home/mathematics/calculus---differential-calculus---problem-set-ii- Examples and solved problems - related to derivability and continuity of functions; changing the independent variable in a differential equation; finding the N-th derivative of functions. http://www.thelearningpoint.net/home/mathematics/calculus---differential-calculus---problem-set-iii - Examples and solved problems - related to increasing and decreasing functions; maxima, minima and extreme values; Rolle's Theorem. http://www.thelearningpoint.net/home/mathematics/calculus---differential-calculus---problem-set-iv -  Examples and solved problems - Slope of tangents to a curve, points of inflexion, convexity and concavity of curves, radius of curvature and asymptotes of curves, sketching curves. http://www.thelearningpoint.net/home/mathematics/calculus---differential-calculus---problem-set-v - More examples of investigating and sketching curves, parametric representation of curves. http://www.thelearningpoint.net/home/mathematics/calculus---introducing-integral-calculus- Theory and definitions. What integration means, the integral and the integrand. Indefinite integrals, integrals of common functions. Definite integration and properties of definite integrals; Integration by substitution, integration by parts, the LIATE rule, Integral as the limit of a sum. Important forms encountered in integration. http://www.thelearningpoint.net/home/mathematics/calculus---integral-calculus-problem-set-i - Examples and solved problems - elementary examples of integration involving trigonometric functions, polynomials; integration by parts; area under curves. http://www.thelearningpoint.net/home/mathematics/calculus---integral-calculus-problem-set-ii - Examples and solved problems - integration by substitution, definite integrals, integration involving trigonometric and inverse trigonometric ratios. http://www.thelearningpoint.net/home/mathematics/calculus---integral-calculus-problem-set-iii- Examples and solved problems - Reduction formulas, reducing the integrand to partial fractions, more of definite integrals. http://www.thelearningpoint.net/home/mathematics/calculus---integral-calculus-problem-set-iv -Examples and solved problems - More of integrals involving partial fractions, more complex substitutions and transformations http://www.thelearningpoint.net/home/mathematics/calculus---integral-calculus-problem-set-v - Examples and solved problems - More complex examples of integration, examples of integration as the limit of a summation of a series. http://www.thelearningpoint.net/home/mathematics/calculus---introduction-to-differential-equations-and-solved-problems - Theory and definitions. What a differential equation is; ordinary and partial differential equations; order and degree of a differential equation; linear and non linear differential equations; General, particular and singular solutions; Initial and boundary value problems; Linear independence and dependence; Homogeneous equations; First order differential equations; Characteristic and auxiliary equations. Introductory problems demonstrating these concepts. Introducing the concept of Integrating Factor (IF). http://www.thelearningpoint.net/home/mathematics/calculus---differential-equations-problem-set-ii - Examples and solved problems - Solving linear differential equations, the D operator, auxiliary equations. Finding the general solution ( CF + PI ) http://www.thelearningpoint.net/home/mathematics/calculus---differential-equations-problem-set-iii - More complex cases of differential equations. http://www.thelearningpoint.net/home/mathematics/calculus---differential-equations-problem-set-iv - Still more differential equations.   http://...Multiple Variable Calculus  http://www.thelearningpoint.net/home/mathematics/calculus---multiple-variables---part-i   http://www.thelearningpoint.net/home/mathematics/calculus---multiple-variables---part-2   http://www.thelearningpoint.net/home/mathematics/calculus---multiple-variables---part-3     http://...Computer Science and Programminghttp://... http://... Data Structures and Algorithms Arrays : Popular Sorting and Searching Algorithms   http://www.thelearningpoint.net/computer-science/arrays-and-sorting-bubble-sort--with-c-program-source-code- One of the most elementary sorting algorithms to implement - and also very inefficient. Runs in quadratic time. A good starting point to understand sorting in general, before moving on to more advanced techniques and algorithms. A general idea of how the algorithm works and a the code for a C program. http://www.thelearningpoint.net/computer-science/arrays-and-sorting-insertion-sort--with-c-program-source-code - Another quadratic time sorting algorithm - an example of dynamic programming. An explanation and step through of how the algorithm works, as well as the source code for a C program which performs insertion sort. http://www.thelearningpoint.net/computer-science/arrays-and-sorting-selection-sort--with-c-program-source-code - Another quadratic time sorting algorithm - an example of a greedy algorithm. An explanation and step through of how the algorithm works, as well as the source code for a C program which performs selection sort. http://www.thelearningpoint.net/computer-science/arrays-and-sorting-shell-sort--with-c-program-source-code- An inefficient but interesting algorithm, the complexity of which is not exactly known. http://www.thelearningpoint.net/computer-science/arrays-and-sorting-merge-sort--with-c-program-source-codeAn example of a Divide and Conquer algorithm. Works in O(n log n) time. The memory complexity for this is a bit of a disadvantage. http://www.thelearningpoint.net/computer-science/arrays-and-sorting-quick-sort--with-c-program-source-code In the average case, this works in O(n log n) time. No additional memory overhead - so this is better than merge sort in this regard. A partition element is selected, the array is restructured such that all elements greater or less than the partition are on opposite sides of the partition. These two parts of the array are then sorted recursively. http://www.thelearningpoint.net/computer-science/arrays-and-sorting-heap-sort--with-c-program-source-code- Efficient sorting algorithm which runs in O(n log n) time. Uses the Heap data structure. Binary Search Algorithm- Commonly used algorithm used to find the position of an element in a sorted array. Runs in O(log n) time. Basic Data Structures and Operations on them    http://www.thelearningpoint.net/home/queues_thumbnail.jpg?attredirects=0http://www.thelearningpoint.net/home/linked_list_thumbnail.jpg?attredirects=0http://www.thelearningpoint.net/home/double_linked_list_thumbnail.jpg?attredirects=0  http://www.thelearningpoint.net/computer-science/data-structures-stacks--with-c-program-source-code Last In First Out data structures ( LIFO ). Like a stack of cards from which you pick up the one on the top ( which is the last one to be placed on top of the stack ). Documentation of the various operations and the stages a stack passes through when elements are inserted or deleted. C program to help you get an idea of how a stack is implemented in code. http://www.thelearningpoint.net/computer-science/data-structures-queues--with-c-program-source-code First in First Out data structure (FIFO). Like people waiting to buy tickets in a queue - the first one to stand in the queue, gets the ticket first and gets to leave the queue first. Documentation of the various operations and the stages a queue passes through as elements are inserted or deleted. C Program source code to help you get an idea of how a queue is implemented in code. http://www.thelearningpoint.net/computer-science/data-structures-singly-linked-list-with-c-program-source-code A self referential data structure. A list of elements, with a head and a tail; each element points to another of its own kind. http://www.thelearningpoint.net/computer-science/data-structures-doubly-linked-list-with-c-program-source-code- A self referential data structure. A list of elements, with a head and a tail; each element points to another of its own kind in front of it, as well as another of its own kind, which happens to be behind it in the sequence. http://www.thelearningpoint.net/computer-science/data-structures-circular-linked-list--with-c-program-source-code Linked list with no head and tail - elements point to each other in a circular fashion.     Tree Data Structures  http://www.thelearningpoint.net/home/binary_search_tree_thumbnail.jpg?attredirects=0  http://www.thelearningpoint.net/computer-science/binary-search-trees A basic form of tree data structures. Inserting and deleting elements in them. Different kind of binary tree traversal algorithms.  http://www.thelearningpoint.net/computer-science/data-structures-heaps-with-c-program-source-code- A tree like data structure where every element is lesser (or greater) than the one above it. Heap formation, sorting using heaps in O(n log n) time.  http://www.thelearningpoint.net/computer-science/data-structures-height-balanced-trees - Ensuring that trees remain balanced to optimize complexity of operations which are performed on them.   http://...Graphs and Graph Algorithmshttp://...  https://sites.google.com/a/thelearningpoint.net/www/computer-science/goog_20517018 http://www.thelearningpoint.net/home/dijkstra_thumbnail.jpg?attredirects=0  http://www.thelearningpoint.net/computer-science/algorithms-graph-traversal--depth-first-search--with-c-program-source-code - Traversing through a graph using Depth First Search in which unvisited neighbors of the current vertex are pushed into a stack and visited in that order. http://www.thelearningpoint.net/computer-science/algorithms-graph-traversal---breadth-first-search-with-c-program-source-code - Traversing through a graph using Breadth First Search in which unvisited neighbors of the current vertex are pushed into a queue and then visited in that order. http://www.thelearningpoint.net/computer-science/algorithms-minimum-spanning-trees-in-graphs---the-kruskal-algorithm--with-c-program-source-code- Finding the Minimum Spanning Tree using the Kruskal Algorithm which is a greedy technique. Introducing the concept of Union Find. http://www.thelearningpoint.net/computer-science/algorithms-minimum-spanning-trees-in-graphs---prims-algorithm-with-c-program-source-code- Finding the Minimum Spanning Tree using the Prim's Algorithm. http://www.thelearningpoint.net/computer-science/algorithms-shortest-path-in-graphs---dijkstra-algorithm--with-c-program-source-code- Popular algorithm for finding shortest paths : Dijkstra Algorithm. http://www.thelearningpoint.net/computer-science/algorithms-all-to-all-shortest-paths-in-graphs---floyd-warshall-algorithm-with-c-program-source-code- All the all shortest path algorithm: Floyd Warshall Algorithm http://www.thelearningpoint.net/computer-science/algorithms-shortest-paths-in-graphs---the-bellman-ford-algorithm- Another common shortest path algorithm : Bellman Ford Algorithm. Popular Algorithms in Dynamic Programming   http://www.thelearningpoint.net/computer-science/algorithms-an-introduction-to-dynamic-programming A technique used to solve optimization problems, based on identifying and solving sub-parts of a problem first. http://www.thelearningpoint.net/computer-science/algorithms-dynamic-programming---the-integer-knapsack-problemAn elementary problem, often used to introduce the concept of dynamic programming. http://www.thelearningpoint.net/computer-science/algorithms-dynamic-programming---matrix-chain-multiplication Given a long chain of matrices of various sizes, how do you parenthesize them for the purpose of multiplication - how do you chose which ones to start multiplying first? http://www.thelearningpoint.net/computer-science/algorithms-dynamic-programming---longest-common-subsequence Given two strings, find the longest common sub sequence between them. Dynamic Programming Algorithms covered previously: Insertion Sort, Floyd Warshall Algorithm Algorithms which we already covered, which are example of dynamic programming.   http://...Greedy Algorithms http://...  http://www.thelearningpoint.net/computer-science/algorithms-greedy-algorithms---fractional-knapsack-problems-task-scheduling-problem - Elementary problems in Greedy algorithms - Fractional Knapsack, Task Scheduling. Along with C Program source code. http://www.thelearningpoint.net/computer-science/algorithms-greedy-algorithms---data-compression-using-huffman-encodingCompression using Huffman Trees. A greedy technique for encoding information. http://...Commonly Asked Programming Interview Questions - from Microsoft/Google/Facebook/Amazon interviews   Programming Interview Questions with Solutions - Microsoft, Google, Facebook, Amazon http://...A Collection of C Programs  http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous  Miscellaneous C Programs http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-Computing-the-Area-of-a-Circle-in-C- http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-check-for-Armstrong-Numbers http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-for-Bezier-Curves http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-implementing-the-Bisection-Method-Numerical-Computing- http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-demonstrating-the-use-of-Bitwise-Operators http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-for-an-Expression-Evaluator http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-demonstrate-File-Handling-Functions http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-demonstrate-the-Gaussian-Elimination-Method http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-compute-the-GCD-HCF-of-two-numbers http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-solve-the-Josephus-Problem http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-demonstrate-operations-on-Matrices http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-implementing-the-Newton-Raphson-Method-Numerical-Computing- http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-check-whether-a-string-is-a-palindrome-or-not http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-print-the-Pascal-Triangle http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-display-Prime-Numbers-using-the-sieve-of-Eratosthenes http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-for-the-Producer---Consumer-Problem http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-for-the-Reader---Writer-Problem http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-demonstrate-the-Dining-Philosopher-problem http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-reverse-the-order-of-words-in-a-sentence http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-reverse-a-string http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-demonstrate-the-values-in-the-series-expansion-of-exp-x-sin-x-cos-x-tan-x- http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-demonstrate-common-operations-on-Sets http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-Program-to-solve-Simultaneous-Linear-Equations-in-two-variables http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-program-to-display-the-total-number-of-words-the-number-of-unique-words-and-the-frequency-of-each-word http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-program-to-display-the-IP-address http://www.thelearningpoint.net/computer-science/c-programs---miscellaneous#TOC-C-program-implementing-the-Jacobi-method-Numerical-Computing- http://...Introduction to Digital Electronic Circuits and Boolean logic   http://www.thelearningpoint.net/home/electrical-science-and-engineering/introduction-to-combinational-circuits--part-1/combinational_circuits.jpg?attredirects=0 http://www.thelearningpoint.net/home/electrical-science-and-engineering/introduction-to-the-number-system--part-1 Introducing number systems. Representation of numbers in Decimal, Binary,Octal and Hexadecimal forms. Conversion from one form to the other. http://www.thelearningpoint.net/home/electrical-science-and-engineering/number-system--part-2 Binary addition, subtraction and multiplication. Booth's multiplication algorithm. Unsigned and signed numbers. http://www.thelearningpoint.net/home/electrical-science-and-engineering/introduction-to-boolean-algebra--part-1Binary logic: True and false. Logical operators like OR, NOT, AND. Constructing truth tables. Basic postulates of Boolean Algebra. Logical addition, multiplication and complement rules. Principles of duality. Basic theorems of boolean algebra: idempotence, involution, complementary, commutative, associative, distributive and absorption laws. http://www.thelearningpoint.net/home/electrical-science-and-engineering/boolean-algebra--part-2De-morgan's laws. Logic gates. 2 input and 3 input gates. XOR, XNOR gates. Universality of NAND and NOR gates. Realization of Boolean expressions using NAND and NOR. Replacing gates in a boolean circuit with NAND and NOR. http://www.thelearningpoint.net/home/electrical-science-and-engineering/understanding-karnaugh-maps--part-1 Introducing Karnaugh Maps. Min-terms and Max-terms. Canonical expressions. Sum of products and product of sums forms. Shorthand notations. Expanding expressions in SOP and POS Forms ( Sum of products and Product of sums ). Minimizing boolean expressions via Algebraic methods or map based reduction techniques. Pair, quad and octet in the context of Karnaugh Maps. http://www.thelearningpoint.net/home/electrical-science-and-engineering/karnaugh-maps--part-2 Map rolling. Overlapping and redundant groups. Examples of reducing expressions via K-Map techniques. http://www.thelearningpoint.net/home/electrical-science-and-engineering/introduction-to-combinational-circuits--part-1 Combinational circuits: for which logic is entirely dependent of inputs and nothing else. Introduction to Multiplexers, De-multiplexers, encoders and decoders.Memories: RAM and ROM. Different kinds of ROM - Masked ROM, programmable ROM. http://www.thelearningpoint.net/home/electrical-science-and-engineering/combinational-circuits--part-2 Static and Dynamic RAM, Memory organization. http://www.thelearningpoint.net/home/electrical-science-and-engineering/introduction-to-sequential-circuits--part-1  Introduction to Sequential circuits. Different kinds of Flip Flops. RS, D, T, JK. Structure of flip flops. Switching example. Counters and Timers. Ripple and Synchronous Counters. http://www.thelearningpoint.net/home/electrical-science-and-engineering/sequential-circuits--part-2 ADC or DAC Converters and conversion processes. Flash Converters, ramp generators. Successive approximation and quantization errors. http://...

http://www.ankurgupta.net/category/gate/ This contains some useful notes for gate which are prepared by a student in IISC (Ankur Gupta). Also, you can listen to relevant lectures on some topics by IIT Professors on youtube or NPTEL . Most of the time these are useful. Also, if you are not clear on a topic, search the relevant lecture on youtube by Stanford or MIT professors. The main part is practicing questions. For that, you can join test series by ACE Academy  (http://www.aceenggacademy.com/gate/gate-2015/gate-2015-all-india-online-test-series) which I think is the best. If you want, you can join test series from Gateforum etc., but I do not have any experience with them.

GATE needs conceptual clarity to crack. But it also needs systematic approach and dedicated preparation. I see couple of good answers out here. Use online tools like http://doubtpoint.com/ On doubtpoint you can post doubts and ask experts It uses all the facility rich editor, online video support like FB videos and youtube videos. Picture and link upload and support. Structured data and streamed approach. You can form a study group and so on. Go with curated questions and follow important tags and subjects. Follow users like Quora Like Quora spend your time on doubtpoint. Spend some time on Quality blogs and interesting approach from the students who have already made it with great score. Hope this helps