func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e6 + 5;   const int mod = 1e9 + 7;   struct edge {     int u, v, t, c, id;   } e[N];   int n, m;   vector<edge> s[N];   bool cmp(edge a, edge b) { return a.c < b.c; }   struct TwoSat {     static const int N = ::N << 1;     int dfn[N], low[N], id[N], st[N], _st, _, cc;     vector<int> g[N];     int mark[N], n;     void init(int _n) {       for (int i = ((n = _n << 1)) - 1; i >= (0); --i) g[i].clear();     }     int new_node() {       for (int i = (0); i < (2); i++) g[n++].clear();       return n / 2 - 1;     }     void addedge(int a, int va, int b, int vb) {       a = a << 1 | va;       b = b << 1 | vb;       g[a].push_back(b);       g[b ^ 1].push_back(a ^ 1);     }     void add_set(int a, int va) {       a = a << 1 | va;       g[a ^ 1].push_back(a);     }     void add_then(int a, int va, int b, int vb) { addedge(a, va, b, vb ^ 1); }     void add_or(int a, int va, int b, int vb) { addedge(a, va ^ 1, b, vb); }     void add_xor(int a, int va, int b, int vb) {       addedge(a, va, b, vb);       addedge(b, vb, a, va);     }     void dfs(int c, vector<int> g[]) {       dfn[c] = low[c] = ++cc;       st[_st++] = c;       for (auto t : g[c])         if (!dfn[t])           dfs(t, g), low[c] = min(low[c], low[t]);         else if (!id[t])           low[c] = min(low[c], dfn[t]);       if (low[c] == dfn[c]) {         ++_;         do {           id[st[--_st]] = _;         } while (st[_st] != c);       }     }     void find() {       fill_n(dfn, n, cc = 0);       fill_n(low, n, _st = 0);       fill_n(id, n, _ = 0);       for (int i = (0); i < (n); i++)         if (!dfn[i]) dfs(i, g);       for (int i = (0); i < (n); i++) --id[i];       return;     }     bool solve() {       find();       for (int i = 0; i < n; i += 2) {         if (id[i] == id[i + 1]) return 0;         mark[i >> 1] = (id[i] > id[i + 1]);       }       return 1;     }   } ts;   int p = 0;   void solve(int u) {     sort(s[u].begin(), s[u].end(), cmp);     for (int i = 0, j; i < (int)s[u].size();) {       j = i;       while (j < (int)s[u].size() && s[u][j].c == s[u][i].c) j++;       if (j - i >= 3) {         cout <<  No n ;         exit(0);       }       if (j - i == 2) {         int x = s[u][i].id, y = s[u][i + 1].id;         ts.add_or(x, 0, y, 0);       }       i = j;     }     for (int i = (0); i < ((int)s[u].size() - 1); i++) {       ts.addedge(p + i + 1, 0, p + i, 0);     }     for (int i = (0); i < ((int)s[u].size()); i++) {       int x = s[u][i].id;       ts.addedge(x, 0, p + i, 0);       if (i != (int)s[u].size() - 1) ts.addedge(x, 0, p + i + 1, 1);     }   }   void link() {     p = m;     for (int i = (1); i < (n + 1); i++) {       solve(i);       p += (int)s[i].size();     }   }   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     cin >> n >> m;     int L = 0, R = 0;     for (int i = (1); i < (m + 1); i++) {       cin >> e[i].u >> e[i].v >> e[i].c >> e[i].t;       e[i].id = i - 1;       R = max(R, e[i].t);       s[e[i].u].push_back(e[i]);       s[e[i].v].push_back(e[i]);     }     int ans = -1;     while (L <= R) {       int mid = (L + R) / 2;       ts.init(3 * m);       link();       for (int i = (1); i < (m + 1); i++)         if (e[i].t > mid) {           ts.add_set(e[i].id, 1);         }       if (ts.solve()) {         ans = mid;         R = mid - 1;       } else         L = mid + 1;     }     if (ans == -1)       cout <<  No ;     else {       ts.init(3 * m);       link();       for (int i = (1); i < (m + 1); i++)         if (e[i].t > ans) ts.add_set(e[i].id, 1);       ts.solve();       cout <<  Yes n ;       vector<int> task;       for (int i = 0; i < m; ++i)         if (!ts.mark[i]) task.push_back(i + 1);       cout << ans <<     << (int)task.size() <<   n ;       for (auto v : task) cout << v <<    ;     }     return 0;   }   