```
int minPathSum(vector<vector<int>>& grid) {
int m = grid.size(), n = grid[0].size();
for (int i = 1; i < m; i++) grid[i][0] += grid[i-1][0];
for (int j = 1; j < n; j++) grid[0][j] += grid[0][j-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];
}
```