279. Perfect Squares

{leetcode}/problems/perfect-squares/[LeetCode - Perfect Squares^]

当前节点最小的值为当前值减去一个平方对应数字的值再加一，再众多选项中的最小值。

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

Example 1:

Input: n = 12
Output: 3
Explanation: 12 = 4 + 4 + 4.

Example 2:

Input: n = 13
Output: 2
Explanation: 13 = 4 + 9.

link:{sourcedir}/_0279_PerfectSquares.java[role=include]