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
 
  
1 1000
 

Sample Output
 
  
Case #1: 840
 

Source
 

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;
}

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转载自blog.csdn.net/xieshimao/article/details/7050834