A number whose only prime factors are 2,3,5 or 7 is called a humble number. The sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 24, 25, 27, ... shows the first 20 humble numbers. Write a program to find and print the nth element i…

P2723 丑数 Humble Numbers 52通过 138提交 题目提供者该用户不存在 标签USACO 难度普及/提高- 提交  讨论  题解 最新讨论 暂时没有讨论 题目背景 对于一给定的素数集合 S = {p1, p2, ..., pK},考虑一个正整数集合,该集合中任一元素的质因数全部属于S.这个正整数集合包括,p1.p1*p2.p1*p1.p1*p2*p3...(还有其它).该集合被称为S集合的"丑数集合".注意:我们认为1不是一个丑数. 题目描述 你的工作是对于输入的集…

给定一个素数集合 S = { p[1],p[2],...,p[k] },大于 1 且素因子都属于 S 的数我们成为丑数(Humble Numbers or Ugly Numbers),记第 n 大的丑数为 h[n]. 算法 1: 一种最容易想到的方法当然就是从 2 开始一个一个的判断一个数是否为丑数.这种方法的复杂度约为 O( k * h[n]),铁定超时(如果你这样做而没有超时,请跟 tenshi 联系) 算法 2: 看来只有一个一个地主动生成丑数了 : 我最早做这题的时候,用的是一种比较烂的…

USACO  Humble Numbers 这题主要是两种做法,第一种是比较常(jian)规(dan)的-------------用pq(priority_queue)维护,每次取堆中最小值(小根堆),用这个值松(mei)弛(ju)一遍所有的素数,大概是O(n*k*logn)的,所以--------闭眼睛T啊!! 冷静一下,我们来看第二种做法: 显然,在第一种做法中,我们重复计算了堆中的好多值,而这些我们可以通过记录一个地址来优化. 我们假设已经求出了前i个丑数,对于第(i+1)个丑数,我们可以…

DP 水题 Description A number whose only prime factors are 2,3,5 or 7 is called a humble number. The sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 24, 25, 27, ... shows the first 20 humble numbers. Write a program to find and print…

Description A number whose only prime factors are 2,3,5 or 7 is called a humble number. The sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 24, 25, 27, ... shows the first 20 humble numbers. Now given a humble number, please write…

Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u Submit Status Practice HDU 1058 Description A number whose only prime factors are 2,3,5 or 7 is called a humble number. The sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 1…

The number of divisors(约数) about Humble Numbers Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2044    Accepted Submission(s): 1006 Problem DescriptionA number whose only prime factors are 2,3,…

Humble Numbers Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 9988 Accepted: 4665 Description A number whose only prime factors are 2,3,5 or 7 is called a humble number. The sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20,…

Humble Numbers Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 18238    Accepted Submission(s): 7934 Problem Description A number whose only prime factors are 2,3,5 or 7 is called a humble numbe…