Patterns
Pattern recognition is the fastest path from random grinding to interview confidence.
Dynamic Programming
Define states and transitions; memoize or tabulate.
479 problems
Greedy
Sort + choose locally best option with proof of correctness.
411 problems
Hash Map
Trade space for speed with key-value lookups and frequency counting.
293 problems
DFS / Backtracking
Recursive exploration with undo for search spaces.
256 problems
Two Pointers
Use two indices moving through a sequence to find pairs, remove elements, or partition.
215 problems
Binary Search
Halve the search space on sorted data or monotonic answer functions.
210 problems
Sort
Master the Sort coding pattern with curated problems.
191 problems
Prefix Sum
Precompute cumulative sums for O(1) range queries.
184 problems
Queue / BFS
Explore level by level for shortest paths and multi-source floods.
160 problems
Stack / Monotonic Stack
Track candidates with LIFO order or monotonic properties.
138 problems
Sliding Window
Maintain a dynamic subarray/substring window with add/remove invariants.
137 problems
Bit Manipulation
Use bits as compact sets or arithmetic shortcuts.
130 problems
Heap / Priority Queue
Always extract min/max in logarithmic time.
85 problems
Union Find
Disjoint sets for connectivity and component merging.
54 problems
Sorted List
Master the Sorted List coding pattern with curated problems.
53 problems
Tree Traversal
Preorder, inorder, postorder, and level-order walks.
49 problems
Trie
Prefix trees for dictionary and string prefix queries.
48 problems
Graph
Master the Graph coding pattern with curated problems.
43 problems
Linked List Pointers
Dummy heads, fast/slow pointers, and in-place rewiring.
42 problems
Segment Tree
Master the Segment Tree coding pattern with curated problems.
34 problems
Constructive Algorithms
Master the Constructive Algorithms coding pattern with curated problems.
33 problems
Fenwick Tree
Master the Fenwick Tree coding pattern with curated problems.
31 problems
Tree
Master the Tree coding pattern with curated problems.
31 problems
Kmp Algorithm
Master the Kmp Algorithm coding pattern with curated problems.
27 problems
Counting Sort
Master the Counting Sort coding pattern with curated problems.
27 problems
Graph Algorithms
DFS/BFS, topological sort, Dijkstra, and MST ideas.
26 problems
Dijkstras Algorithm
Master the Dijkstras Algorithm coding pattern with curated problems.
23 problems
Tree Dp
Master the Tree Dp coding pattern with curated problems.
21 problems
Rabin Karp Algorithm
Master the Rabin Karp Algorithm coding pattern with curated problems.
20 problems
Topological Sort
Order nodes in a DAG for course-schedule style problems.
16 problems
Manachers Algorithm
Master the Manachers Algorithm coding pattern with curated problems.
9 problems
Kadane's Algorithm
Maximum subarray via running local optima.
9 problems
Merge Sort
Master the Merge Sort coding pattern with curated problems.
7 problems
Floyd Warshall Algorithm
Master the Floyd Warshall Algorithm coding pattern with curated problems.
6 problems
A Search Algorithm
Master the A Search Algorithm coding pattern with curated problems.
6 problems
Tarjans Offline Lca Algorithm
Master the Tarjans Offline Lca Algorithm coding pattern with curated problems.
5 problems
Boyer Moore Majority Vote Algorithm
Master the Boyer Moore Majority Vote Algorithm coding pattern with curated problems.
4 problems
Bucket Sort
Master the Bucket Sort coding pattern with curated problems.
4 problems
Linear Search
Master the Linear Search coding pattern with curated problems.
4 problems
Wqs Binary Search
Master the Wqs Binary Search coding pattern with curated problems.
4 problems
Kruskals Algorithm
Master the Kruskals Algorithm coding pattern with curated problems.
3 problems
Tree Diameter
Master the Tree Diameter coding pattern with curated problems.
3 problems
Cartesian Tree
Master the Cartesian Tree coding pattern with curated problems.
2 problems
Partial Sort
Master the Partial Sort coding pattern with curated problems.
2 problems
Quad Tree
Master the Quad Tree coding pattern with curated problems.
1 problems
2d Fenwick Tree
Master the 2d Fenwick Tree coding pattern with curated problems.
1 problems
Quick Sort
Master the Quick Sort coding pattern with curated problems.
1 problems
Suffix Tree
Master the Suffix Tree coding pattern with curated problems.
1 problems
Ukkonens Algorithm
Master the Ukkonens Algorithm coding pattern with curated problems.
1 problems
Kruskal Algorithm
Master the Kruskal Algorithm coding pattern with curated problems.
1 problems
Weiszfelds Algorithm
Master the Weiszfelds Algorithm coding pattern with curated problems.
1 problems
Tarjans Algorithm
Master the Tarjans Algorithm coding pattern with curated problems.
1 problems
Prefix Sum Binary Search
Master the Prefix Sum Binary Search coding pattern with curated problems.
1 problems
Sorted Dict
Master the Sorted Dict coding pattern with curated problems.
1 problems
Welzls Algorithm
Master the Welzls Algorithm coding pattern with curated problems.
1 problems
Euclidean Algorithm
Master the Euclidean Algorithm coding pattern with curated problems.
1 problems
Radix Sort
Master the Radix Sort coding pattern with curated problems.
1 problems
Contructive Algorithms
Master the Contructive Algorithms coding pattern with curated problems.
1 problems
Random Algorithms
Master the Random Algorithms coding pattern with curated problems.
1 problems
Paritial Sort
Master the Paritial Sort coding pattern with curated problems.
1 problems
Bellman Ford Algorithm
Master the Bellman Ford Algorithm coding pattern with curated problems.
1 problems
Prims Algorithm
Master the Prims Algorithm coding pattern with curated problems.
1 problems
Two Sorted Lists
Master the Two Sorted Lists coding pattern with curated problems.
1 problems
Maximum Spanning Tree
Master the Maximum Spanning Tree coding pattern with curated problems.
1 problems
Mos Algorithm
Master the Mos Algorithm coding pattern with curated problems.
1 problems
Persistent Segment Tree
Master the Persistent Segment Tree coding pattern with curated problems.
1 problems