Leetcode 1202. Smallest String With Swaps

Given a string and allowed index swap pairs, view pairs as edges in a graph to find connected components where characters can be freely permuted; for each component, sort its characters and place them in the component's indices to produce the lexicographically smallest string. This requires near-linear component-finding (union-find or DFS) and sorting per component to handle up to 1e5 elements.