[LeetCode]Unique Paths@python

最新推荐文章于 2020-05-24 10:58:12 发布

benjamin_sunny_li

最新推荐文章于 2020-05-24 10:58:12 发布

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文章标签： leetcode dp

本文链接：https://blog.youkuaiyun.com/weixin_38111819/article/details/79180742

版权

A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below).

The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in the diagram below).

How many possible unique paths are there?

Above is a 3 x 7 grid. How many possible unique paths are there?

Note: m and n will be at most 100.

思路：类似于这种动态规划的题，要注意第一行和第一列的区别。

class Solution(object):
    def uniquePaths(self, m, n):
        """
        :type m: int
        :type n: int
        :rtype: int
        """
        res = [[1 for _ in range(n)] for _ in range(m)]
        for i in range(1,m):
            for j in range(1,n):
                res[i][j] = res[i-1][j]+res[i][j-1]
        return res[-1][-1]