class Solution {    public int numSquares(int n) {         int[] dp = new int[n + 1];        dp[1] = 1;        for (int i = 2; i <= n; i++) {            int t = (int) Math.sqrt(i);            if (t * t == i) {//square number                dp[i] = 1;                continue;            }            int min = Integer.MAX_VALUE;            int jj = 0;            for (int j = t; j >= 1; j--) {                jj = j * j;                min = Math.min(min, dp[jj] + dp[i - jj]);            }            dp[i] += min;        }        return dp[n];    }}