• Time:O(mn)
• Space:O(1)

## C++

``````class Solution {
public:
int minPathSum(vector<vector<int>>& grid) {
const int m = grid.size();
const int n = grid[0].size();

for (int i = 0; i < m; ++i)
for (int j = 0; j < n; ++j)
if (i > 0 && j > 0)
grid[i][j] += min(grid[i - 1][j], grid[i][j - 1]);
else if (i > 0)
grid[i][0] += grid[i - 1][0];
else if (j > 0)
grid[0][j] += grid[0][j - 1];

return grid[m - 1][n - 1];
}
};
``````

## JAVA

``````class Solution {
public int minPathSum(int[][] grid) {
final int m = grid.length;
final int n = grid[0].length;

for (int i = 0; i < m; ++i)
for (int j = 0; j < n; ++j)
if (i > 0 && j > 0)
grid[i][j] += Math.min(grid[i - 1][j], grid[i][j - 1]);
else if (i > 0)
grid[i][0] += grid[i - 1][0];
else if (j > 0)
grid[0][j] += grid[0][j - 1];

return grid[m - 1][n - 1];
}
}
``````

## Python

``````class Solution:
def minPathSum(self, grid: List[List[int]]) -> int:
m = len(grid)
n = len(grid[0])

for i in range(m):
for j in range(n):
if i > 0 and j > 0:
grid[i][j] += min(grid[i - 1][j], grid[i][j - 1])
elif i > 0:
grid[i][0] += grid[i - 1][0]
elif j > 0:
grid[0][j] += grid[0][j - 1]

return grid[m - 1][n - 1]
``````