2017ACM/ICPC广西邀请赛 A Math Problem

A Math Problem

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 0    Accepted Submission(s): 0

Problem Description

You are given a positive integer n, please count how many positive integers k satisfy kk≤n .

 

Input

There are no more than 50 test cases.

Each case only contains a positivse integer n in a line.

1≤n≤1018

 

Output

For each test case, output an integer indicates the number of positive integers k satisfy kk≤n in a line.

 

Sample Input

1 4

 

Sample Output

1 2

 

 

题解：完全是一道水题

10的18次方   所以我们使用long long int 长整数打表    记录i的i次方    我们可以发现当i=16的时候   16的16次方已经大于了10的18次方

直接打表循环判断一下就AC了

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <algorithm>
#include <cstring>
#include <math.h>
using namespace std;
 long long int a[20];
 long long int jug(int x)
{
   long long int ans=1;
    for(int i=1;i<=x;++i)
    {
        ans=ans*x;
    }
    return ans;
}
void init()
{
    for(int i=1;i<20;++i)
    {
        a[i]=jug(i);
    }
}
int main()
{
    init();
  long long int n;

    while(~scanf("%lld",&n))
    {
        for(int i=1;i<=15;++i)
        {
            if(a[i]>n)
            {
                printf("%d
",i-1);
                break;
            }
        }
        if(a[15]<=n)
        printf("15
");
    }
     return 0;
}
//0ms  AC

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