LeetCode Unique Paths

题目

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.

 

只能向下或向右，求从左上角到右下角的路线数。

动态规划，到(i,j)格的路线数p(i,j)=p(i-1,j)+p(i,j-1)。

 

代码：

class Solution {public:int uniquePaths(int m, int n) {vector<vector<int>> paths(m,vector<int>(n,1));for(int i=1;i<m;i++)for(int j=1;j<n;j++)paths[i][j]=paths[i-1][j]+paths[i][j-1];return paths[m-1][n-1];    }};