leetcode(62)不同路径

class Solution {
    public int uniquePaths(int m, int n) {
        int[][] arrays = new int[m+1][n+1];
        for(int i=1;i<m+1;++i){
            for(int j=1;j<n+1;++j){
                if(i==1||j==1){
                    arrays[i][j]=1;
                }else{
                    arrays[i][j]=arrays[i-1][j]+arrays[i][j-1];
                }
            }
        }
        return arrays[m][n];
    }
}

class Solution {
    public int uniquePaths(int m, int n) {
        int min = Math.min(m,n);
        int max = Math.max(m,n);
        int[][] arrays = new int[2][min];
        int cur = 0;
        for(int i=0;i<m+n-1;++i){
            for(int j=0;j<min;++j){
                if(i-j>=0||i-j<=max){
                    if(j==0||i-j==0){
                        arrays[cur][j]=1;
                    }else{
                        arrays[cur][j]=arrays[1-cur][j-1]+arrays[1-cur][j];
                    }
                }
            }
            cur = 1-cur; 
        }
        return arrays[1-cur][min-1];
    }
}