HDU 4133 反素数

 

StrangeStandard

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 70    Accepted Submission(s): 31

Problem Description

Nowadays, WHUACMer use a strange standard to evaluate a natural number.The evaluating value of a natural number is the amount of it’s divisors.If a number m has bigger evaluating value than all the numbers smaller than it, we call it a good number. Now give you a number n, find the maximum good number which is not bigger than n.

 

Input

The first line contains a single integer T(T<=10), indicating the number of test cases.
For each test case,there is only one line which only contains one number n(1 <= n <= 2 000 000 000)

 

Output

For each test case,output the case number first,then output the maximum good number which is not bigger than n.

 

Sample Input

11000

 

Sample Output

Case #1: 840

 

Source

武汉大学第五届E鸣杯程序设计大赛

 

Recommend

lcy

 

很明显的反素数搜索。

照着模板写就行了。。

 

我的代码：

#include<stdio.h>__int64 prime[16]={2,3,5,7,11,13,17,19,23,29,31,37,41,43,47};__int64 n,cnter,ans;void dfs(__int64 cur,__int64 cnt,__int64 power,__int64 sub){    __int64 i;    if(cur>n)        return;    if(cnt==cnter&&cur<ans)        ans=cur;    if(cnt>cnter)    {        ans=cur;        cnter=cnt;    }    __int64 p=prime[sub];    for(i=1;i<=power;i++)    {        if(cur*p>n)            break;        dfs(cur*p,cnt*(i+1),i,sub+1);        p=p*prime[sub];    }}int main(){    int t,T;    scanf("%d",&T);    for(t=1;t<=T;t++)    {        scanf("%I64d",&n);        cnter=0,ans=0;        dfs(1,1,50,0);        printf("Case #%d: %I64d\n",t,ans);    }    return 0;}