Leetcode 3665. Twisted Mirror Path Count

• Leetcode 3665. Twisted Mirror Path Count
  • 1. 解题思路
  • 2. 代码实现

• 题目链接：3665. Twisted Mirror Path Count

1. 解题思路

这一题相较于上一题就直接很多了，就是一个动态规划，直接写就行了。

2. 代码实现

给出python代码实现如下：

MOD = 10**9+7class Solution:def uniquePaths(self, grid: List[List[int]]) -> int:n, m = len(grid), len(grid[0])DIRECTION = {0: (1, 0), 1: (0, 1)}@lru_cache(None)def dp(i, j, direction):if i == n-1 and j == m-1:return 1if i < 0 or i >= n or j < 0 or j >= m:return 0if grid[i][j] == 0:return (dp(i+1, j, 0) + dp(i, j+1, 1)) % MODwhile 0 <= i < n and 0 <= j < m and grid[i][j] == 1:direction = 1-directiondx, dy = DIRECTION[direction]i, j = i+dx, j+dyreturn dp(i, j, direction) % MODreturn dp(0, 0, 0)

提交代码评测得到：耗时耗时2733ms，占用内存306.37MB。