func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxN = 100050, mod = 1000000007;   ;   int n, ans, k;   int fa[maxN], c[maxN];   int getfa(int u) {     if (fa[u] == u) return u;     int t = fa[u];     fa[u] = getfa(fa[u]);     while (c[u] < 0) c[u] += mod;     while (c[t] < 0) c[t] += mod;     c[u] = (c[u] + c[t]) % mod;     return fa[u];   }   int main() {     scanf( %d , &n);     for (int i = 1; i <= n; i++) {       fa[i] = i;       c[i] = 0;     }     int v, x;     for (int i = 1; i <= n; i++) {       scanf( %d , &k);       for (int j = 1; j <= k; j++) {         scanf( %d%d , &v, &x);         int t = getfa(v);         fa[t] = i;         while (c[v] < 0) c[v] += mod;         while (x < 0) x += mod;         c[t] = (c[v] + x) % mod;         while (c[t] < 0) c[t] += mod;         while (ans < 0) ans += mod;         ans = (ans + c[t]) % mod;       }     }     printf( %d n , ans);     return 0;   }   