1. class Solution {
    2. public:
    3.     int minimumCost(int n, vector<vector<int>>& e) {
    4.         sort(e.begin(), e.end(), [&](vector<int>& lth, vector<int>& rth) {
    5.             return lth[2] < rth[2];
    6.         });
    7.         vector<int> f(n + 1);
    8.         iota(f.begin(), f.end(), 0);
    9.         function<int(int)> get = [&](int x) { return x == f[x] ? x : f[x] = get(f[x]); };
    11.         int res = 0, cnt = 0;
    12.         for(int i = 0; i < e.size(); i++) {
    13.             int x = get(e[i][0]), y = get(e[i][1]);
    14.             if(x == y) continue;
    15.             f[x] = y;
    16.             res += e[i][2];
    17.             cnt ++;
    18.         }
    19.         return cnt == n - 1 ? res : -1;
    20.     }
    21. };