B. A Trivial Problem

题目连接：

http://www.codeforces.com/contest/633/problem/B

Description

Mr. Santa asks all the great programmers of the world to solve a trivial problem. He gives them an integer m and asks for the number of positive integers n, such that the factorial of n ends with exactly m zeroes. Are you among those great programmers who can solve this problem?

Input

The only line of input contains an integer m (1 ≤ m ≤ 100 000) — the required number of trailing zeroes in factorial.

Output

First print k — the number of values of n such that the factorial of n ends with m zeroes. Then print these k integers in increasing order.

Sample Input

Sample Output

5

5 6 7 8 9

Hint

题意

让你输出哪些数的阶乘后面恰好有k个0

题解：

首先阶乘后面的0的个数，就是2的因子数和5的因子数的最小值

显然2的因子数肯定比5多，所以不用考虑2，直接考虑5就好了

我是二分找的，当然在这个复杂度下面，直接暴力就好了

代码

#include<bits/stdc++.h>

using namespace std;

long long m;

long long check(long long n)

{

    long long num = 0;

    while(n)

    {

        num+=n/5;

        n=n/5;

    }

    return num;

}

int get(long long k)

{

    long long l = 0,r = 1e15,ans = r;

    while(l<=r)

    {

        long long mid = (l+r)/2;

        if(check(mid)>=k)r=mid-1,ans=mid;

        else l=mid+1;

    }

    return ans;

}

int main()

{

    scanf("%lld",&m);

    long long ans = get(m),ans2 = get(m+1);

    if(check(ans)==m&&check(ans2-1)==m)

    {

        cout<<ans2-ans<<endl;

        for(int i=ans;i<ans2;i++)

            cout<<i<<" ";

        cout<<endl;

    }

    else

        return puts("0");

}

巴特西

Manthan, Codefest 16 B. A Trivial Problem 二分数学

B. A Trivial Problem

题目连接：

Description

Input

Output

Sample Input

Sample Output

Hint

题意

题解：

代码

最新文章

热门文章

巴特西

Manthan, Codefest 16 B. A Trivial Problem 二分 数学

B. A Trivial Problem

题目连接：

Description

Input

Output

Sample Input

Sample Output

Hint

题意

题解：

代码

最新文章

热门文章

Manthan, Codefest 16 B. A Trivial Problem 二分数学