func_code_string: #include <bits/stdc++.h>   using namespace std;   const int INF = 0x3f3f3f3f, maxn = 10;   int Pow(int a, int b) {     int ans = 1;     while (b) {       if (b & 1) ans = (long long)ans * a % 1000000007;       a = (long long)a * a % 1000000007;       b >>= 1;     }     return ans;   }   int main() {     int n, k;     while (~scanf( %d%d , &n, &k)) {       int ans = (long long)Pow(k, k - 1) * Pow(n - k, n - k) % 1000000007;       printf( %d n , ans);     }     return 0;   }   