Solution.cpp

class Solution {
public:
    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
        int n = s.size();
        int p[n];
        iota(p, p + n, 0);
        vector<char> d[n];
        function<int(int)> find = [&](int x) -> int {
            if (p[x] != x) {
                p[x] = find(p[x]);
            }
            return p[x];
        };
        for (auto e : pairs) {
            int a = e[0], b = e[1];
            p[find(a)] = find(b);
        }
        for (int i = 0; i < n; ++i) {
            d[find(i)].push_back(s[i]);
        }
        for (auto& e : d) {
            sort(e.rbegin(), e.rend());
        }
        for (int i = 0; i < n; ++i) {
            auto& e = d[find(i)];
            s[i] = e.back();
            e.pop_back();
        }
        return s;
    }
};