hdu 1058 Humble Numbers

通过不断的寻找2^a*3^b*5^c*7^d按顺序的数就可以了……

#include <iostream>
#include <cmath>
using namespace std;
__int64 ans[6000];
int find(int a,int b,int c,int d)
{
    int aa=a>b?b:a;
    int bb=c>d?d:c;
    return aa>bb?bb:aa;
}   
void init()
{
    int a,b,c,d,min,a1,b1,c1,d1;
    a=b=c=d=0;
    ans[0]=1;
    for(int i=1;i<=5842;i++)
    {
        min=find(a1=ans[a]*2,b1=ans[b]*3,c1=ans[c]*5,d1=ans[d]*7);
        ans[i]=min;
        if(min==a1)a++;
        if(min==b1) b++;
        if(min==c1) c++;
        if(min==d1) d++;
    }
}
int main()
{
    int n;
    init();
    while(scanf("%d",&n),n)
    {
        if(n%10==1&&n%100!=11)
            printf("The %dst humble number is %d.\n",n,ans[n-1]);
        else if(n%10==2&&n%100!=12)
            printf("The %dnd humble number is %d.\n",n,ans[n-1]);
        else if(n%10==3&&n%100!=13)
            printf("The %drd humble number is %d.\n",n,ans[n-1]);
        else printf("The %dth humble number is %d.\n",n,ans[n-1]);
    }
    return 0;
}