leetcode (62) a different path

Different paths

Problem-solving ideas: a bottom-up dynamic programming +

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];
    }
}