A2Z DSA Sheet, reimagined & free

Start here: input and output, data types, conditionals, loops, functions and the basics of time complexity.

Digit manipulation, palindromes, GCD and HCF, Armstrong numbers, divisors and prime checks.

Get comfortable with recursion by printing sequences, summing numbers, computing factorials, reversing arrays and checking palindromes.

Hashing theory and counting element frequencies, including the highest and lowest frequency element.

Selection, bubble, insertion, merge and quick sort, plus recursive bubble and insertion sort.

From the largest element to Kadane's algorithm, 2Sum, 3Sum and 4Sum, matrix rotation, merging intervals, count inversions and reverse pairs.

Lower and upper bound, rotated sorted arrays, binary search on answers like Koko Eating Bananas and Aggressive Cows, and search in 2D matrices.

Parentheses, palindromes, anagrams, isomorphic strings, Roman numerals, atoi and substring problems.

Singly and doubly linked lists: insertion, deletion, reversal, cycle detection with the tortoise and hare, sorting and cloning with random pointers.

Subsequences, subsets, combination sums, palindrome partitioning, N-Queens, Rat in a Maze, M-Coloring and Sudoku Solver.

Checking and setting bits, counting set bits, powers of two, XOR tricks and generating the power set.

Implement stacks and queues, convert between infix, prefix and postfix, solve monotonic stack problems and build LRU and LFU caches.

Longest substring without repeating characters, fruit into baskets, nice subarrays, minimum window substring and more.

Binary heaps and priority queues: Kth largest and smallest, merging sorted lists, task scheduler, median of a data stream and top K frequent elements.

Assign cookies, fractional knapsack, jump game, meeting rooms, job sequencing, candy and interval scheduling.

Recursive, iterative and Morris traversals, height and diameter, tree views, LCA, maximum width, construction from traversals and serialization.

Search, insert and delete in a BST, floor and ceil, Kth smallest element, validation, LCA, inorder successor and recovering a BST.

BFS and DFS, cycle detection, topological sort, shortest paths with Dijkstra, Bellman-Ford and Floyd-Warshall, minimum spanning trees, disjoint sets and SCCs.

The full DP series: 1D DP, DP on grids, subsets, strings and stocks, LIS and partition DP, from Climbing Stairs to Burst Balloons.

Implement a trie, count distinct substrings and solve maximum XOR problems with a bitwise trie.

String hashing, Rabin-Karp, the Z-function, KMP and the LPS array, shortest palindrome and longest happy prefix.