Smallest String Reachable Through Allowed Index Swaps

### Problem Each pair gives two zero-based positions whose characters may be swapped any number of times. Return the lexicographically smallest string reachable from s using these allowed swaps. ```cpp class Solution { public: string smallestStringWithSwaps(string s, vector<vector<int>>& pairs); }; ``` ### Examples **Example 1:** ```text Input: s = "cbad", pairs = [[0,1]] Output: "bcad" Explanation: Only positions0 and1 can exchange characters, so their b,c values are sorted there. ``` **Example 2:** ```text Input: s = "zxy", pairs = [[0,1],[1,2]] Output: "xyz" Explanation: The connected chain permits every permutation of the three positions. ``` ### Constraints - s has length 1 to 100000 and uses lowercase English letters. - There are 0 to 100000 index pairs. - Both labels in every pair lie in `[0,s.length-1]`. ### Contract considerations The permitted operations may have many sequences, but their lexicographically minimum string is a unique result. ```hint Read the boundary condition May an allowed pair be used repeatedly, and what result is required when there are no allowed pairs? ``` ### Boundary reminders The permitted operations may have many sequences, but their lexicographically minimum string is a unique result.