LeetCode||64. Minimum Path Sum

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.

Note: You can only move either down or right at any point in time.

Example 1:

[[1,3,1], [1,5,1], [4,2,1]]

Given the above grid map, return 7. Because the path 1→3→1→1→1 minimizes the sum.

这题还是类似的动态规划，判断条件变为取两个数之间最小的。

因此，例子中的结果矩阵为：

[[1,4,5], [2,7,6], [6,8,7]]

所以结果为7

class Solution(object):    def minPathSum(self, grid):        """        :type grid: List[List[int]]        :rtype: int        """        row = len(grid)        col = len(grid[0])        res = [[0 for i in range(col)] for j in range(row)]        res[0][0] = grid[0][0]        for i in range(1, row):        res[i][0] = res[i-1][0] + grid[i][0]        for i in range(1, col):        res[0][i] = res[0][i-1] + grid[0][i]        for i in range(1, row):        for j in range(1, col):        res[i][j] = min(res[i-1][j], res[i][j-1]) + grid[i][j]        return res[-1][-1]