279. Perfect Squares

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：

 public class Solution {
     public int numSquares(int n) {
         if(n<=2)
         return n;

         int min=n,t=0;
         for(int i=2;i*i<=n;i++)
         {
             int c=i*i;
             if(n%c==0)
             t=n/c;
             else
                 t=n/c+numSquares(n%c);
                 if(t<min)
                 min=t;
         }
         return min;
     }
 }