Selected LeetCode Problems

Updated October 09, 2026

Topics
  1. Contest Setup
  2. Binary Search
  3. Dynamic Programming
  4. Range Queries
  5. Priority Queues
  6. Hashing
  7. Strings
  8. Graphs and Trees
  9. Combinatorics
  10. Data Structure Design
  11. Databases
  12. Selected LeetCode Problems

A running list of LeetCode problems worth remembering, each labeled with the topic or technique it turns on. It doubles as an index into the topic pages on this blog, and I add to it as I go.

The list

Problem Topic
1520 — Maximum Number of Non-Overlapping Substrings Sorting and Greedy
2213 — Longest Substring of One Repeating Character Segment Tree
732 — My Calendar III Dynamic Segment Tree, Lazy Propagation
2286 — Booking Concert Tickets in Groups Segment Tree Walk, Amortized Analysis
2827 — Number of Beautiful Integers in the Range Digit DP
679 — 24 Game Range DP, Backtracking
30 — Substring with Concatenation of All Words Rolling Hash
214 — Shortest Palindrome Rolling Hash
1923 — Longest Common Subpath Rolling Hash, Binary Search
652 — Find Duplicate Subtrees XOR / Merkle Hashing
1948 — Delete Duplicate Folders in System XOR / Merkle Hashing
Count Subarrays with Distant Sums Fenwick Tree, Coordinate Compression
1971 — Find if Path Exists in Graph Graphs, Adjacency (CSR)
3067 — Count Pairs of Connectable Servers in a Weighted Tree Network Trees
1641 — Count Sorted Vowel Strings Combinatorics, Stars and Bars
1621 — Number of Sets of K Non-Overlapping Line Segments Combinatorics, Stars and Bars
1146 — Snapshot Array Persistent Data Structures
311 — Sparse Matrix Multiplication Sparse Matrix, CSR
400 — Nth Digit Digit Counting
4053 — Minimum Operations to Make Every Element Palindromic Precompute, Binary Search
3357 — Minimize the Maximum Adjacent Element Difference Binary Search on the Answer