func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, k, g;   int a[100010];   int gcd(int x, int y) {     if (y == 0) return x;     return gcd(y, x % y);   }   bool used[100010];   int main() {     scanf( %d%d , &n, &k);     g = 0;     for (int i = 1; i <= n; i++) {       scanf( %d , &a[i]);       a[i] %= k;       g = gcd(g, a[i]);       g = gcd(g, k - a[i]);     }     int cnt = 0;     for (int i = 0; i < k; i += g) {       if (used[i] == 1) break;       used[i] = 1;       cnt++;     }     printf( %d n , cnt);     for (int i = 0; i < k; i++)       if (used[i] == 1) printf( %d  , i);   }   