62. 不同路径 @Python @Go

原题

https://leetcode.cn/problems/unique-paths/description/

思路

动态规划

复杂度

时间：O(m * n)
空间：O(m * n)

Python代码

class Solution:
    def uniquePaths(self, m: int, n: int) -> int:
        dp = [[0] * n for i in range(m)]
        dp[0] = [1] * n
        if m == 1:
            return dp[0][-1]
        for i in range(1, m):
            for j in range(n):
                if j == 0:
                    dp[i][j] = dp[i - 1][j]
                else:
                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1]
        return dp[-1][-1]

Go代码

func uniquePaths(m int, n int) int {
	// 创建二维数组, 储存结果
	dp := make([][]int, m)
	for i := 0; i < m; i++ {
		dp[i] = make([]int, n)
	}
	for j := 0; j < n; j++ {
		dp[0][j] = 1
	}
	if m == 1 {
		return dp[0][n-1]
	}
	for i := 1; i < m; i++ {
		for j := 0; j < n; j++ {
			if j == 0 {
				dp[i][j] = dp[i-1][j]
			} else {
				dp[i][j] = dp[i-1][j] + dp[i][j-1]
			}
		}
	}
	return dp[m-1][n-1]
}