LeetCode-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.

Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

Analysis:

A DP solution like the Coin Changes.

Solution:

public class Solution {
    public int numSquares(int n) {
        int[] nums = new int[n+1];

        for (int i=1;i<=n;i++){
            nums[i] = Integer.MAX_VALUE;
            for (int j=1;j*j<=i;j++){
                nums[i] = Math.min(nums[i], nums[i-j*j]+1);
            }
        }
        return nums[n];
    }
}