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  • leetcode------Unique Paths

    标题: Unique Paths
    通过率: 32.6%    
    难度: 中等

    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.

    第(i,j)步的上一步只可能是从(i-1,j)或者是(i,j-1)来的,那么F(i,j)=F(i-1,j)+F(i,j-1)

    一个二维数组现将第一行第一列都填成1,然后从(1,1)到(m-1,n-1);

    代码如下:

     1 public class Solution {
     2     public int uniquePaths(int m, int n) {
     3         int[][]result=new int[m][n];
     4         for(int i=0;i<m;i++){
     5             result[i][0]=1;
     6         }
     7         for(int i=0;i<n;i++){
     8             result[0][i]=1;
     9         }
    10         for(int i=1;i<m;i++){
    11             for(int j=1;j<n;j++){
    12                 result[i][j]=result[i-1][j]+result[i][j-1];
    13             }
    14         }
    15         return result[m-1][n-1];
    16     }
    17 }
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  • 原文地址:https://www.cnblogs.com/pkuYang/p/4315366.html
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