LeetCode 62

原题：

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?

题意：机器人在左上角，终点在右下角，每次只能向下或者向右移动，问达到终点有多少条不同的路径。

代码和思路：

public class Solution {public int uniquePaths(int m, int n) {//new一个同样大小的数组    int[][] grid = new int[m][n];    for(int i = 0; i<m; i++){        for(int j = 0; j<n; j++){        //如果在第一行或者第一列，那么把“走法”置为1，因为只有一种方法可以达到这一点            if(i==0||j==0)                grid[i][j] = 1;            //例如2行2列，那么我可以从1行2列或者2行1列到达，那么可能性就是可达路径相加            else                grid[i][j] = grid[i][j-1] + grid[i-1][j];        }    }    return grid[m-1][n-1];}}