求最大质因数位置-优快云博客

本文链接：https://blog.youkuaiyun.com/AC_AC_ACGIRL/article/details/43454983

本文介绍了一个编程问题，即确定一个整数的最大质因数的位置，并提供了一段C语言代码实现。输入一个整数n（0<n<1000000），程序将输出该数最大质因数的位置。

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Largest prime factor

Time Limit: 5000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 7531 Accepted Submission(s): 2690

Problem Description

Everybody knows any number can be combined by the prime number.
Now, your task is telling me what position of the largest prime factor.
The position of prime 2 is 1, prime 3 is 2, and prime 5 is 3, etc.
Specially, LPF(1) = 0.

Input

Each line will contain one integer n(0 < n < 1000000).

Output

Output the LPF(n).

Sample Input

Sample Output

Author

Wiskey

Source

HDU 2007-11 Programming Contest_WarmUp

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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#define N 1000000
int prime[N];

int main()
{int i,j,k=1;
    memset(prime,0,sizeof(prime));
    prime[1]=0;
    for(i=2; i<=N; i++)
        if(!prime[i])
        {
            prime[i]=k;
            for(j=i+i;j<N;j+=i)
                prime[j]=k;
            k++;
        }
    int p;
    while(scanf("%d",&p)!=EOF)
    {
            printf("%d\n",prime[p]);
    }
    return 0;
}