func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 200005;   int n, t, k, ret;   int a[N];   int sum[N];   int main() {     scanf( %d%d%d , &n, &t, &k);     int all = 0;     sum[0] = 1;     a[0] = 1;     for (int i = 1; i <= t; i++) {       scanf( %d , &a[i]);       sum[i] = sum[i - 1] + a[i];       if (a[i] < a[i - 1]) ret += a[i - 1] - a[i];     }     if (ret + a[t] > k || n - t < k) {       printf( -1 n );       return 0;     }     printf( %d n , n);     int fa = 1, now = 2;     int need = n - t - k;     for (int i = 1; i <= t; i++) {       while (now <= sum[i]) {         printf( %d %d n , fa, now);         if (fa != sum[i - 1] && now != sum[i] && need > 0) {           fa++;           need--;         }         now++;       }       fa = sum[i - 1] + 1;     }   }   