Data Structures & Algorithms

Find the smallest letter greater than the target in a cyclically ordered character list.

LeetCode notes on the Trapping Rain Water problem.

LeetCode notes on the Container With Most Water problem.

Sort first and then insert by position to reconstruct a queue described by height and preceding-person counts.

Rearrange non-negative integers so their concatenation forms the largest integer.

Generate all string permutations using recursive backtracking, deduplicate them, and sort them lexicographically.

Find the top K frequent elements using frequency counting with sorting or a min-heap.

Find the majority element using a counting map or candidate cancellation.

Find the element that appears only once using counting or XOR.

Move all zeroes to the end of the array while preserving the relative order of non-zero elements.