Grid Game LeetCode solution in C++

1
class Solution {
2
 public:
3
  long long gridGame(vector<vector<int>> &grid) {
4
    int n = grid[0].size();
5
    vector<long long> pre1(n + 1, 0);
6
    vector<long long> pre2(n + 1, 0);
7
    long long s = 0, ans = 0;
8
    grid[0][0] = 0;
9
    grid[1][n - 1] = 0; // Picked by First Robot
10
    for (int i = 0; i < n; i++) {
11
      pre1[i + 1] = pre1[i] + grid[0][i];
12
      pre2[i + 1] = pre2[i] + grid[1][i];
13
      s += grid[0][i];
14
    }
15
    for (int i = 1; i <= n; i++) {
16
      ans = max(min(s - pre1[i], pre2[i]), ans);
17
    }
18
    return ans;
19
  }
20
};