Data Structures & Algorithms

Use a map to count character occurrences while preserving input order to find the first character that appears only once in a stream.

LeetCode notes on the brute-force solution for Subarray Sum Equals K.

Record two implementations of cyclic left rotation of a string: slicing and concatenation, and three reversals.

LeetCode notes on the brute-force solution for Maximal Square.

Sort five cards, treat jokers as 0, and use the gaps between non-zero cards to determine whether they can form a straight.

LeetCode notes on the brute-force solution for Daily Temperatures.

Record two implementations for replacing spaces with %20: character-by-character concatenation and preallocated storage.

LeetCode notes on Daily Temperatures with brute force and a monotonic stack.

Record recursive and stack-based methods for outputting a linked list from tail to head.

LeetCode notes on Sliding Window Maximum using brute force, a priority queue, and a monotonic deque.