环保部网站官网建设项目审批各类资源关键词
class Solution {public int numTrees(int n) {int[] dp = new int[n+1];dp[0] = 1;dp[1] = 1;for(int i = 2;i <= n ; i++){for(int j = 1; j <= i;j++){dp[i] +=dp[j-1]*dp[i-j];}}return dp[n];}
}
class Solution {public int numTrees(int n) {int[] dp = new int[n+1];dp[0] = 1;dp[1] = 1;for(int i = 2;i <= n ; i++){for(int j = 1; j <= i;j++){dp[i] +=dp[j-1]*dp[i-j];}}return dp[n];}
}