题解 | 矩阵的最小路径和

#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param matrix int整型二维数组 the matrix
# @return int整型
#
class Solution:
    def minPathSum(self , matrix: List[List[int]]) -> int:
        # write code here
        n, m = len(matrix), len(matrix[0])
        dp = [[0 for _ in range(m)] for _ in range(n)]
        dp[0][0] = matrix[0][0]
        for i in range(1, m):
            dp[0][i] = dp[0][i-1] + matrix[0][i]
        for j in range(1, n):
            dp[j][0] = dp[j-1][0] + matrix[j][0]
        for i in range(1, n):
            for j in range(1, m):
                dp[i][j] = min(dp[i-1][j]+matrix[i][j], dp[i][j-1] + matrix[i][j])
        return dp[n-1][m-1]