时间执行期间暗战 [英] Time Running out during execution

问题描述

这是从项目欧拉问题3。什么是600851475143.我做节目最大的主要因素，但这个数量问题是一个12digit号码，我不得不采取的数据类型，只要长。当我尝试执行对小数目，如13195的程序，它工作正常，但所需数量不是！我试着在各种编译器运行它在线，并在Cygwin，我在我的电脑上使用。但是，这个项目停止三个输出后，向前迈进。

HELP！

 ＃包括LT＆;＆stdio.h中GT;
诠释的main（）
{
    长长的NUM = 600851475143;
    INT I = 1，J，K，大= 0;
    //的printf（\\ n输入一个数字：）;
    // scanf函数（％D，试验＃）;
    而（I＆LT; = NUM​​）
    {
        K = 0;
        如果（NUM％我== 0）
        {
            J = 1;
            而（J＆LT; = I）
            {
                如果（我引用％j == 0）
                    ķ++;
                J ++;
            }            如果（K == 2）
            {
                的printf（\\ n％d是一个首要因素，我）;
                如果（I＆GT;大）
                    大= I;
            }
        }
        我++;
    }    的printf（\\ nBiggest主要因素为％d，大）;
    返回0;
}
 

解决方案

 ＃包括LT＆;＆stdio.h中GT;诠释主（）{
    长长的NUM = 600851475143LL;
    长长的I = 1; //它必须是时的主要是同一类型的NUM。    对于（i = 2; I * I＆LT; = NUM​​ ++我）{
        而（NUM％我== 0）{
            NUM / = I;
        }
    }
    的printf（\\ nBiggest首要因素是LLD％，NUM == 1 I  -  1：NUM）;
    返回0;
}
 

This is 3rd Problem from Project Euler. What is the biggest prime factor of 600851475143. I've done the program but this number in question being a 12digit number, I had to take the datatype as long long. When I try to execute the program for small number, such as 13195, it works fine but for the desired number it doesn't! I tried running it in various compilers online and also on Cygwin which I use on my PC. But the programs stops going forward after three outputs.

HELP!!

#include<stdio.h>
int main()
{
    long long num = 600851475143;
    int i=1,j,k, big=0;
    // printf("\nEnter a number:");
    //scanf("%d",&num);
    while(i<=num)
    {
        k=0;
        if(num%i==0)
        {
            j = 1;
            while( j <= i)
            {
                if( i % j == 0)
                    k++;
                j++;
            }

            if(k==2)
            {
                printf("\n%d is a prime factor",i);
                if( i > big)
                    big = i;
            }
        }
        i++;
    }

    printf("\nBiggest prime factor is %d", big);
    return 0;
}

解决方案

#include<stdio.h>

int main(){
    long long num = 600851475143LL;
    long long i=1;//It must be the same type for num when was the prime.

    for(i=2;i*i<=num;++i){
        while(num % i ==0){
            num /= i;
        }
    }
    printf("\nBiggest prime factor is %lld", num == 1 ? i - 1 : num);
    return 0;
}

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