func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 1e6 + 10;   const int M = 2;   struct Node {     int parent, rela;     void set(int p, int r) {       parent = p;       rela = r;     }   } node[maxn];   int Find(int x) {     int tmp_p;     if (node[x].parent != x) {       tmp_p = node[x].parent;       node[x].parent = Find(node[x].parent);       node[x].rela = (node[x].rela + node[tmp_p].rela) % M;     }     return node[x].parent;   }   void Merge(int a, int b, int p, int q, int d) {     node[p].parent = q;     node[p].rela = (node[b].rela - node[a].rela - d + M) % M;   }   int n, m;   const long long mod = 1e9 + 7;   void init() {     for (int i = 0; i < maxn; ++i) {       node[i].parent = i, node[i].rela = 0;     }   }   long long powerMod(int x, int k) {     long long res = 1;     long long base = x;     while (k) {       if (k & 1) res = res * base % mod;       base = base * base % mod;       k >>= 1;     }     return res;   }   int main() {     init();     int num = 0;     cin >> n >> m;     int res = 1;     for (int i = 0; i < m; ++i) {       int a, b, c;       cin >> a >> b >> c;       int p = Find(a);       int q = Find(b);       if (p != q)         Merge(a, b, p, q, c ^ 1);       else {         if ((node[a].rela - node[b].rela + 2) % 2 != 1 - c) res = 0;       }     }     if (res == 0)       cout << res << endl;     else {       for (int i = 1; i <= n; ++i)         if (Find(i) == i) num++;       cout << powerMod(2, num - 1) << endl;     }     return 0;   }   