func_code_string: #include <bits/stdc++.h>   using namespace std;   int read() {     char c = getchar();     while (!isdigit(c)) c = getchar();     int num = 0;     while (isdigit(c)) num = num * 10 + c -  0 , c = getchar();     return num;   }   void write(int num) {     if (num >= 10) write(num / 10);     putchar(num % 10 +  0 );   }   int u[50001], v[50001], c[50001], t[50001];   vector<int> e[50001];   bool cmp(int a, int b) { return c[a] < c[b]; }   int head[500001], ver[2000001], nxt[2000001], sz;   void addedge(int u, int v) { ver[++sz] = v, nxt[sz] = head[u], head[u] = sz; }   int dfn[500001], low[500001];   int vis[500001], stk[500001];   int now, top, cnt, scc[500001];   void tarjan(int x) {     dfn[x] = low[x] = ++now;     stk[++top] = x, vis[x] = 1;     for (int i = head[x]; i; i = nxt[i])       if (!vis[ver[i]])         tarjan(ver[i]), low[x] = min(low[x], low[ver[i]]);       else if (vis[ver[i]] == 1)         low[x] = min(low[x], dfn[ver[i]]);     if (dfn[x] == low[x]) {       scc[x] = ++cnt, vis[x] = 2;       while (stk[top] != x) {         scc[stk[top]] = cnt;         vis[stk[top]] = 2;         --top;       }       --top;     }   }   bool _2sat(int n) {     now = cnt = 0;     for (int i = 1; i <= n * 2; i++) vis[i] = 0;     for (int i = 1; i <= n * 2; i++)       if (!vis[i]) tarjan(i);     for (int i = 1; i <= n; i++)       if (scc[i] == scc[i + n]) return 0;     return 1;   }   int main() {     int n, m;     n = read(), m = read();     for (int i = 1; i <= m; i++) {       u[i] = read(), v[i] = read(), c[i] = read(), t[i] = read();       e[u[i]].push_back(i), e[v[i]].push_back(i);     }     int tot = m;     for (int i = 1; i <= n; i++) {       int tmp = 0;       sort(e[i].begin(), e[i].end(), cmp);       for (int j = 1; j < e[i].size(); j++)         if (c[e[i][j]] == c[e[i][j - 1]]) {           if (tmp) {             puts( No );             return 0;           }           tmp = j;         }       if (tmp) {         addedge(e[i][tmp], m * 5 + e[i][tmp - 1]);         addedge(e[i][tmp - 1], m * 5 + e[i][tmp]);         addedge(m * 5 + e[i][tmp - 1], e[i][tmp]);         addedge(m * 5 + e[i][tmp], e[i][tmp - 1]);         for (int j = 0; j < e[i].size(); j++)           if (j != tmp && j != tmp - 1) addedge(e[i][j], m * 5 + e[i][j]);       } else {         for (int j = 1; j < e[i].size(); j++) {           addedge(j + tot, j + 1 + tot);           addedge(j + 1 + tot + e[i].size(), j + tot + e[i].size());           addedge(j + 1 + tot + m * 5, j + tot + m * 5);           addedge(j + tot + e[i].size() + m * 5,                   j + 1 + tot + e[i].size() + m * 5);         }         for (int j = 0; j < e[i].size(); j++) {           addedge(e[i][j], j + 1 + tot);           addedge(e[i][j], j + 1 + tot + e[i].size());           addedge(j + 1 + tot + m * 5, e[i][j] + m * 5);           addedge(j + 1 + tot + e[i].size() + m * 5, e[i][j] + m * 5);         }         for (int j = 1; j < e[i].size(); j++) {           addedge(e[i][j], j + tot + m * 5);           addedge(e[i][j - 1], j + 1 + tot + e[i].size() + m * 5);           addedge(j + tot, e[i][j] + m * 5);           addedge(j + 1 + tot + e[i].size(), e[i][j - 1] + m * 5);         }       }       tot += e[i].size() * 2;     }     int tmp = sz;     int l = 0, r = 1000000001;     while (l < r) {       int mid = (l + r) / 2;       for (int i = 1; i <= m * 10; i++)         while (head[i] > tmp) head[i] = nxt[head[i]];       sz = tmp;       for (int i = 1; i <= m; i++)         if (t[i] > mid) addedge(i, i + m * 5);       if (_2sat(m * 5))         r = mid;       else         l = mid + 1;     }     if (l == 1000000001) {       puts( No );       return 0;     }     puts( Yes );     write(l), putchar(   );     for (int i = 1; i <= m * 10; i++)       while (head[i] > tmp) head[i] = nxt[head[i]];     sz = tmp;     for (int i = 1; i <= m; i++)       if (t[i] > l) addedge(i, i + m * 5);     _2sat(m * 5);     int res = 0;     for (int i = 1; i <= m; i++)       if (scc[i] < scc[i + m * 5]) ++res;     write(res), putchar(  n );     for (int i = 1; i <= m; i++)       if (scc[i] < scc[i + m * 5]) write(i), putchar(   );     putchar(  n );   }   