a solution for the 2023 ec3 beginner competitive programming final contest's problem B: waterbottles in c++.

B_waterbottles.cpp

#include <bits/stdc++.h>
using namespace std;
#define int long long

int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int H, W, K;
  cin >> H >> W >> K;
  
  long long sum = 0, input;
  for (int i = 0; i < H * W; i++) {
    cin >> input;
    sum += input;
  }
  
  cout << sum - (2 * W * H - H - W) * K;
}