POJ1338-Ugly Numbers

http://poj.org/problem?id=1338

写写水题放松放松- -#

#include<iostream>
#include<queue>
using namespace std;
typedef pair<unsigned long,int>node_type;
int main(void)
{
    unsigned long result[1500];
    priority_queue<node_type,vector<node_type>,greater<node_type> >Q;
    Q.push(make_pair(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;
    }
    int n;
    while(cin>>n&&n)
       cout<<result[n-1]<<endl;
    return 0;
}

上面是新写的用STL实现。

#include<cstdio>
#include<algorithm>
using namespace std;
int main(void)
{
    int a[1501],x,y,z,n,i;
    x=y=z=a[1]=1;
    for(i=2;i<=1500;i++)
    {
        a[i]=min(2*a[x],min(3*a[y],5*a[z]));
        if(2*a[x]==a[i])x++;
        if(3*a[y]==a[i])y++;
        if(5*a[z]==a[i])z++;
    }
    while(scanf("%d",&n),n)
       printf("%d\n",a[n]);
    return 0;
}