func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1E6 + 5, K = 1E6 + 5, INF = 1E9 + 7;   int n, k, c, v, ans = 0, dsu[K];   char s[N];   vector<int> adj[N];   struct node {     int l, r, xo;     node(int _l = 0, int _r = 0, int _xo = 0) : l(_l), r(_r), xo(_xo) {}     int get() { return min(l, r); }     inline void operator+=(node oth) {       l = min(INF, l + oth.l);       r = min(INF, r + oth.r);     }   } val[K];   pair<int, int> trace(int u) {     if (dsu[u] < 0) {       return {u, 0};     } else {       pair<int, int> tmp = trace(dsu[u]);       dsu[u] = tmp.first;       val[u].xo ^= tmp.second;       return {dsu[u], val[u].xo};     }   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(nullptr);     cin >> n >> k >> (s + 1);     for (int i = 1; i <= k; i++) {       dsu[i] = -1;       val[i] = node(1, 0, 0);       cin >> c;       while (c--) {         cin >> v;         adj[v].push_back(i);       }     }     for (int i = 1; i <= n; i++) {       int typ = (s[i] -  0 ) ^ 1;       if (ans != -1) {         if (adj[i].size() == 1) {           pair<int, int> u = trace(adj[i][0]);           ans -= val[u.first].get();           val[u.first] += node((u.second == typ) * INF, (u.second != typ) * INF);           ans += val[u.first].get();         } else if (adj[i].size() == 2) {           pair<int, int> u = trace(adj[i][0]);           pair<int, int> v = trace(adj[i][1]);           if (u.first != v.first) {             ans -= val[u.first].get() + val[v.first].get();             if (dsu[u.first] > dsu[v.first]) {               swap(u, v);             }             if (u.second ^ v.second ^ typ) {               swap(val[v.first].l, val[v.first].r);               val[v.first].xo = 1;             }             dsu[u.first] += dsu[v.first];             dsu[v.first] = u.first;             val[u.first] += val[v.first];             ans += val[u.first].get();           }         }       }       cout << ans <<   n ;     }   }   