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hdu 3199 Hamming Problem(构造?枚举?)

题意:

For each three prime numbers p1, p2 and p3, let‘s define Hamming sequence Hi(p1, p2, p3), i=1, ... as containing in increasing order all the natural numbers whose only prime divisors are p1, p2 or p3. 

For example, H(2, 3, 5) = 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 25, 27, ... 

So H5(2, 3, 5)=6.

给p1,p2,p3,n,求Hn(p1,p2,p3)

 

思路:

和humble numbers那题一样,,,看代码,,

 

代码:

int p1,p2,p3,x;ll a[1000005];int main(){    while(scanf("%d%d%d%d",&p1,&p2,&p3,&x)!=EOF){        if(p1>p2) swap(p1,p2);        if(p1>p3) swap(p1,p3);        if(p2>p3) swap(p2,p3);        a[1]=1;        int cn=1;        while(cn<=x){            ll temp;            ll ans=INF;            rep2(i,cn,1){                temp=a[i]*p1;   if(temp>a[cn]) ans=min(ans,temp);                temp=a[i]*p2;   if(temp>a[cn]) ans=min(ans,temp);                temp=a[i]*p3;   if(temp>a[cn]) ans=min(ans,temp);                if(temp<=a[cn]) break;            }            a[++cn]=ans;        }        printf("%I64d\n",a[cn]);    }    return 0;}

 

hdu 3199 Hamming Problem(构造?枚举?)