func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e5 + 10;   long long c[N], d[N];   int main() {     long long sum = 0, ans = 0;     int n, k;     scanf( %d %d , &n, &k);     for (int i = 1; i <= n; i++) {       scanf( %lld , &c[i]);       sum += c[i];     }     for (int i = 1; i <= k; i++) {       scanf( %lld , &d[i]);       sum -= c[d[i]];       ans += sum * c[d[i]];       c[d[i]] = 0;     }     for (int i = 2; i <= n; i++) {       ans += c[i] * c[i - 1];     }     ans += c[1] * c[n];     printf( %lld n , ans);     return 0;   }   