小编HWh*_*ang的帖子

当我试图找出不丑的数字时,我遇到了一些问题.丑陋的数字是唯一的素数因子是2,3或5的数字.那么这个数字不是很难看？我试着找出1到100,000,000之间不难看的数字.我的程序可以解决问题,但似乎有点慢.我怎么能让它更快？这是代码:

#include <iostream>
#include <queue>
using namespace std;
typedef pair<unsigned long,int> node_type;
main()
{
    //generates 1500 ugly numbers into result[];
    unsigned long result[1500];
    priority_queue<node_type,vector<node_type>,greater<node_type> > Q;
    Q.push(node_type(1,2));
    for(int i=0;i<1500;i++)
    {
        node_type node = Q.top();
        Q.pop();
    switch(node.second)
    {
        case 2:Q.push(make_pair(node.first*2,2));
        case 3:Q.push(make_pair(node.first*3,3));
        case 5:Q.push(make_pair(node.first*5,5)); 
    }
    result[i]=node.first;
}
/*****************************************************
//Here is the approach I used:
//The initial value of the integer k is 1;
//and will increase by 1 every time 
//k will be checked if it's a ugly number,if not increase …