Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n.

For example, given n = 12, return 3 because 12 = 4 + 4 + 4; given n = 13, return 2 because 13 = 4 + 9.

代码如下：

 1 public class Solution {
 2     public int numSquares(int n) {
 3         if(n<=2)
 4         return n;
 5         
 6         int min=n,t=0;
 7         for(int i=2;i*i<=n;i++)
 8         {
 9             int c=i*i;
10             if(n%c==0)
11             t=n/c;
12             else
13                 t=n/c+numSquares(n%c);
14                 if(t<min)
15                 min=t;
16         }
17         return min;
18     }
19 }