func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, m;   int x[500010], y[500010];   bitset<2010 * 2> A[2010];   void Work() {     for (int i = 1; i <= n; i++) {       int t = i;       for (int j = i + 1; j <= n; j++)         if (A[j][i]) t = j;       swap(A[i], A[t]);       for (int j = 1; j <= n; j++)         if (A[j][i] && j != i) A[j] ^= A[i];     }     for (int i = 1; i <= m; i++)       if (A[y[i]][x[i] + n])         puts( NO );       else         puts( YES );   }   void Init() {     scanf( %d%d , &n, &m);     for (int i = 1; i <= m; i++) {       scanf( %d%d , &x[i], &y[i]);       A[x[i]][y[i]] = 1;     }     for (int i = 1; i <= n; i++) A[i][i + n] = 1;   }   int main() {     Init();     Work();     return 0;   }   