```
class Solution {
public:
int minPathSum(vector<vector<int>>& grid) {
int m = grid.size(),n = grid[0].size();
for (int i = 0; i < m; i++)
{
if (i == 0) continue;
grid[i][0] += grid[i - 1][0];
}
for (int i = 0; i < n; i++)
{
if (i == 0) continue;
grid[0][i] += grid[0][i - 1];
}
for (int i = 1; i < m; i++)
for (int j = 1; j < n; j++)
{
grid[i][j] += min(grid[i - 1][j], grid[i][j - 1]);
}
return grid[m - 1][n - 1];
}
};
```