public class Solution {
    /**
     * 
     * @param m int整型 
     * @param n int整型 
     * @return int整型
     */
    public int uniquePaths (int m, int n) {
        // write code here
        //dp[j][j] =  
        // + dp[i-1][j]   + dp[i][j-1]  
        int[][] dp = new int[m][n];
        for(int i = 0;i< m;i++){
            for(int j = 0;j< n;j++){
                if(i == 0 || j == 0){
                    dp[i][j] = 1;
                    continue;
                }
                dp[i][j] = dp[i-1][j] +dp[i][j-1];
                
            }
        }
        return dp[m-1][n-1];
    }
}