func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, m;   int s, t, ds, dt;   struct edge {     int u, v;   } E[400005];   vector<int> vecr[200005];   int pre[200005];   int find(int x) {     if (x != pre[x]) pre[x] = find(pre[x]);     return pre[x];   }   void Union(int x, int y) { pre[find(x)] = find(y); }   int cpts[200005];   int tot;   int conts[200005];   int contt[200005];   map<int, int> to;   vector<int> dhas;   vector<int> ans;   void output(int pos) {     int siz = vecr[pos].size();     for (int i = 0; i < siz; i++) {       int u = E[vecr[pos][i]].u;       int v = E[vecr[pos][i]].v;       if (find(u) == find(v))         continue;       else {         Union(u, v);         ans.push_back(vecr[pos][i]);       }     }   }   int main() {     scanf( %d%d , &n, &m);     for (int i = 1; i <= n; i++) pre[i] = i;     for (int i = 0; i < m; i++) scanf( %d%d , &E[i].u, &E[i].v);     scanf( %d%d%d%d , &s, &t, &ds, &dt);     for (int i = 0; i < m; i++) {       if (E[i].u == s || E[i].u == t || E[i].v == s || E[i].v == t)         continue;       else if (find(E[i].u) != find(E[i].v)) {         Union(E[i].u, E[i].v);       }     }     for (int i = 1; i <= n; i++)       if (i != s && i != t) cpts[tot++] = find(i);     sort(cpts, cpts + tot);     tot = unique(cpts, cpts + tot) - cpts;     cpts[tot++] = s;     cpts[tot++] = t;     for (int i = 0; i < tot; i++) to[cpts[i]] = i;     memset(conts, -1, sizeof(conts));     memset(contt, -1, sizeof(contt));     for (int i = 0; i < m; i++) {       if (E[i].u == s) conts[to[find(E[i].v)]] = i;       if (E[i].v == s) conts[to[find(E[i].u)]] = i;       if (E[i].u == t) contt[to[find(E[i].v)]] = i;       if (E[i].v == t) contt[to[find(E[i].u)]] = i;       if (find(E[i].u) == find(E[i].v)) vecr[to[find(E[i].u)]].push_back(i);     }     for (int i = 1; i <= n; i++) pre[i] = i;     for (int i = 0; i < tot - 2; i++) {       output(i);       if (conts[i] >= 0 && contt[i] >= 0)         dhas.push_back(i);       else if (conts[i] >= 0) {         ans.push_back(conts[i]);         ds--;       } else if (contt[i] >= 0) {         ans.push_back(contt[i]);         dt--;       }     }     if (dhas.size() == 0) {       ds--;       dt--;       ans.push_back(conts[tot - 1]);       if (ds < 0 || dt < 0)         printf( No n );       else {         printf( Yes n );         for (int i = 0; i < ans.size(); i++) {           printf( %d %d n , E[ans[i]].u, E[ans[i]].v);         }       }     } else {       for (int i = 0; i < dhas.size(); i++) {         if (i == 0) {           ans.push_back(conts[dhas[i]]);           ans.push_back(contt[dhas[i]]);           ds--;           dt--;         } else {           if (ds < dt) {             ans.push_back(contt[dhas[i]]);             dt--;           } else {             ans.push_back(conts[dhas[i]]);             ds--;           }         }       }       if (ds < 0 || dt < 0)         printf( No n );       else {         printf( Yes n );         for (int i = 0; i < ans.size(); i++) {           printf( %d %d n , E[ans[i]].u, E[ans[i]].v);         }       }     }     return 0;   }   