LeetCode 62. Unique Paths

问题描述：

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?

算法思路：

如果机器人要走到 [ i , j ] 位置，他只有两种方法（1）从[ i , j-1 ] 往下走（2）从[ i-1 , j ] 往右走，这样就变成了一个递归问题。使用数组来解，每个位置记录着机器人从start point到达该点的方法

算法：

class Solution {public:    int uniquePaths(int m, int n) {        int arr[100][100];arr[0][0] = 1;for(int i=0;i<m;i++)for (int j = 0; j < n; j++) {    if (i==0&&j==0)        continue;if (i == 0)arr[i][j] = arr[i][j - 1];else if (j == 0)arr[i][j] = arr[i - 1][j];elsearr[i][j] = arr[i - 1][j] + arr[i][j - 1];}return arr[m-1][n-1];    }};