Minimum Path Sum

Problem page:https://leetcode.com/problems/minimum-path-sum

Solution

class Solution:
    def minPathSum(self, grid: List[List[int]]) -> int:
        m, n = len(grid), len(grid[0])
        for i in range(1, m):
            grid[i][0] += grid[i-1][0]
        for i in range(1, n):
            grid[0][i] += grid[0][i-1]
        for i in range(1, m):
            for j in range(1, n):
                grid[i][j] += min(grid[i-1][j], grid[i][j-1])

        return grid[-1][-1]

Complexity

• time: O(n * m)
• space: O(1)