摘要：
You have a total of n coins that you want to form in a staircase shape, where every k-th row must have exactly k coins. Given n, find the total number 阅读全文
摘要：
Write a program to find the nth super ugly number. Super ugly numbers are positive numbers whose all prime factors are in the given prime list primes 阅读全文
摘要：
1. java中的修饰符 a. 权限修饰符 private，默认的，protected，public b. 状态修饰符 static，final c. 抽象修饰符 abstract 2. 类修饰符 public（访问控制符），将一个类声明为公共类，他可以被任何对象访问，一个程序的主类必须是公共类，一 阅读全文
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