62. Unique Paths

动态规划问题

public class Solution {
    public int uniquePaths(int m, int n) {
        int [][] paths=new int[m][n];
        paths[0][0]=1;
        for(int i=0;i<m;i++)
        {
            for(int j=0;j<n;j++)
            {
                int res=0;
                if(i-1>=0)
                    res+=paths[i-1][j];
                if(j-1>=0)
                    res+=paths[i][j-1];
                if(i!=0||j!=0)
                    paths[i][j]=res;
            }
        }
        return paths[m-1][n-1];
    }
}