摘要：
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, 阅读全文
摘要：
263. Ugly Number Write a program to check whether a given number is an ugly number. Ugly numbers are positive numbers whose prime factors only include 阅读全文