leetcode-64-最小路径和

题目描述：

第一次提交：动态规划

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