NeetCode 150
The NeetCode 150 grouped by pattern. Drill one pattern at a time; the pattern is the transferable skill, not the individual problem.
Arrays & Hashing
- 9 problems
- Hash maps for O(1) lookup, prefix sums, frequency counts
Two Pointers
- 5 problems
- Sorted-array convergence, palindrome checks
Sliding Window
- 6 problems
- Variable/fixed windows, longest/shortest substring
Stack
- 7 problems
- Monotonic stack, parentheses, evaluate expressions
Binary Search
- 7 problems
- On answer space, rotated arrays, search 2D
Linked List
- 11 problems
- Fast/slow pointers, reverse, cycle detection, merge
Trees
- 15 problems
- DFS/BFS, BST invariants, recursion patterns
Tries
- 3 problems
- Prefix trees, word search, autocomplete
Heap / Priority Queue
- 7 problems
- Top-k, merge k lists, median of stream
Backtracking
- 9 problems
- Subsets, permutations, combination sum, word search
Graphs
- 13 problems
- DFS/BFS, islands, topological sort, union-find
Advanced Graphs
- 6 problems
- Dijkstra, Prim/Kruskal, Bellman-Ford
1-D DP
- 12 problems
- House robber, coin change, LIS, decode ways
2-D DP
- 11 problems
- Grid paths, edit distance, knapsack, LCS
Greedy
- 8 problems
- Interval scheduling, jump game, gas station
Intervals
- 6 problems
- Merge, insert, non-overlapping, meeting rooms
Math & Geometry
- 8 problems
- Matrix rotation, spiral, happy number, pow
Bit Manipulation
- 7 problems
- XOR tricks, counting bits, single number
How to use it: learn the pattern from one example, then do the rest of the group cold. Re-do anything you could not solve in ~25 minutes. Spaced repetition beats grinding new problems.