【leetcode】Unique Paths

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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.

题解：水题。把一个m*n的矩阵初始化第一行和第一列为1，然后遍历数组中剩下的位置，answer[i][j] = answer[i-1][j]+answer[i][j-1]

代码如下（java）

 1 public class Solution {
 2     public int uniquePaths(int m, int n) {
 3         int[][] answer = new int[m][n];
 4         
 5         for(int i = 0;i < m;i++)
 6             answer[i][0] = 1;
 7         for(int i = 0;i < n;i++)
 8             answer[0][i] = 1;
 9         
10         for(int i = 1;i < m;i++)
11         {
12             for(int j = 1;j < n;j++){
13                 answer[i][j] = answer[i-1][j] + answer[i][j-1];
14             }
15         }
16         
17         return answer[m-1][n-1];
18     }
19 }

【leetcode】Unique Paths,布布扣,bubuko.com

【leetcode】Unique Paths

标签：style   blog   java   color   strong   os   

原文地址：http://www.cnblogs.com/sunshineatnoon/p/3798167.html