dsa2 min read
4Sum [Medium] — Sort + Two Pointers
Find all unique quadruplets summing to target by extending the 3Sum pattern with an outer loop and duplicate skipping.
Read →
All Posts
1575 articles
dsa2 min read
Jump Game II [Medium] — Greedy BFS-Level Jumps
Find minimum number of jumps to reach the last index using greedy BFS-style level tracking.
Read →
dsa2 min read
Gas Station [Medium] — Greedy Linear Scan
Determine the unique starting gas station for a circular route using a greedy one-pass algorithm.
Read →
dsa16 min read
Daily Temperatures [Medium] — Monotonic Stack Masterclass [Amazon, Google]
LeetCode 739 — Find the number of days until a warmer temperature for each day using a monotonic decreasing stack. The key insight: store indices, not temperatures, in the stack. When a warmer day arrives, it is the "next greater element" for every cooler day still waiting on the stack — a fundamental pattern that appears in at least six other LeetCode problems.
Read →
dsa13 min read
Longest Consecutive Sequence [Medium] — HashSet O(n) [Google, Amazon, Facebook]
LeetCode 128 — Find the longest consecutive integer sequence in O(n) using a HashSet. The trick: only start counting from numbers where num-1 is NOT in the set, so each element is visited at most twice total across the entire algorithm.
Read →
Page 72 of 315