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?
Note: m and n will be at most 100.
public class Solution {
public int uniquePaths(int m, int n) {
if(m==1 || n==1) return 1;
int N=m+n-2;
double res=1.0;
//cal N!/(n-1)!*(m-1)!
for(int i=1;i<=m-1;i++){
res=res*(n+i-1)/i;
}
return (int)res;
}
}原文：http://blog.csdn.net/dutsoft/article/details/38579857