Envío 996

Código

#include <algorithm>
#include <bits/stdc++.h>
#include <climits>
using namespace std;

long sum_of(vector<vector<long>> &matrix, int i, int r, int j, int c) {
  long total = matrix[r][c];
  if (i > 0) {
    total -= matrix[i - 1][c];
  }
  if (j > 0) {
    total -= matrix[r][j - 1];
  }
  if (i > 0 and j > 0) {
    total += matrix[i - 1][j - 1];
  }
  return total;
}

int main() {
  int R, C;
  cin >> R >> C;
  vector<vector<long>> matrix(R, vector<long>(C));
  long max_sum = INT_MIN;
  for (int i = 0; i < R; i++) {
    for (int j = 0; j < C; j++) {
      cin >> matrix[i][j];
      max_sum = max(max_sum, matrix[i][j]);
    }
  }

  for (int i = 0; i < R; i++) {
    for (int j = 1; j < C; j++) {
      matrix[i][j] += matrix[i][j - 1];
      max_sum = max(max_sum, matrix[i][j]);
    }
  }
  for (int col = 0; col < C; col++) {
    vector<long> sums(R);
    for (int j = col; j < C; j++) {
      for (int i = 0; i < R; i++) {
        sums[i] = matrix[i][j];
        if (col > 0) {
          sums[i] -= matrix[i][col - 1];
        }
      }
      long gmax = sums[0];
      long currMax = gmax;
      for (int i = 1; i < sums.size(); ++i) {
        currMax = max(sums[i], sums[i] + currMax);
        gmax = max(gmax, currMax);
      }
      max_sum = max(max_sum, gmax);
    }
  }
  cout << max_sum << endl;
}