Day 13 – 4Sum, Subarray Sum = 0, XOR = K, Repeating and Missing Numbers

Today’s focus was on classic variations of subarray sum problems (sum = 0, XOR = k), k-sum extension (4Sum), and optimized detection of missing/repeating elements. LeetCode 18 – 4Sum 1. Brute Force – 4 Nested Loops + Set vector<vector<int>> fourSum...