LeetCode062 Unique Paths

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详细见：leetcode.com/problems/unique-paths

Java Solution: github

package leetcode;import java.util.Arrays;public class P062_UniquePaths {public static void main(String[] args) {System.out.println(new Solution().uniquePaths(3, 3));}/* * 先写一份空间O(m * n)，时间O(m * n)的版本 * 1 ms * 5.22% */static class Solution {    public int uniquePaths(int m, int n) {    if (m < 1 || n < 1)    return 0;        int[][] route = new int[m][n];        Arrays.fill(route[0], 1);        for (int i = 1; i < m; i ++)        route[i][0] = 1;        for (int i = 1; i < m; i ++) {        for (int j = 1; j < n; j ++) {        route[i][j] = route[i - 1][j] + route[i][ j - 1];        }        }        return route[m - 1][n - 1];    }}/* * 1 ms *  5.22%  */static class Solution2 {    public int uniquePaths(int m, int n) {    if (m < 1 || n < 1)    return 0;    if (m > n)    return uniquePaths(n, m);        int[] route = new int[m];        Arrays.fill(route, 1);        for (int i = 1; i < n; i ++)        for (int j = 1; j < m; j ++)        route[j] += route[j - 1];        return route[m - 1];    }}}

C Solution: github

/*    url: leetcode.com/problems/unique-paths    AC 3ms 2.33%*/int uniquePaths(int m, int n) {    int* dp = (int*) malloc(sizeof(int) * n);    int i = 0, j = 0;    for (i = n-1; i > -1; i --) {        dp[i] = 1;    }    for (j = m-2; j > -1; j --) {        for (i = n-2; i > -1; i --) {            dp[i] += dp[i+1];        }    }    i = dp[0];    free(dp);    return i;}int main() {}

Python Solution: github

#coding=utf-8'''    url: leetcode.com/problems/unique-paths    @author:     zxwtry    @email:      zxwtry@qq.com    @date:       2017年4月13日    @details:    Solution: 79ms 10.36%'''class Solution(object):    def uniquePaths(self, m, n):        """        :type m: int        :type n: int        :rtype: int        """        dp = [1] * n        for j in range(m-2, -1, -1):            for i in range(n-2, -1, -1):                dp[i] += dp[i+1]        return dp[0]

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