素数对猜想及线性表链式存储

1.线性表链式存储

https://github.com/BodhiXing/Data_Structure

2.素数对猜想

https://pta.patest.cn/pta/test/17/exam/4/question/261

思路：查找小于N的素数，存入数组，若相邻的相差2，则计数加1。

#include <stdio.h>
#include <math.h>

#define MAX 100000
int a[MAX];

/*是否为素数*/ 
int Is_Prime(int n)
{
    int ret = 1;
    int i;
    for(i=2;i<=sqrt(n);i++)
    {
        if(n%i == 0)
        {
            ret = 0;
            break;
        }
    }
    return ret;
}

void func(int n)
{
    int num = a[0];
    int index = 1,count = 0;
    for(num;num < n;)
    {
        num += 2;
        if(Is_Prime(num))
        {
            a[index] = num;
            if(a[index]-a[index-1] == 2)
                count++;
            index++;
        }
        
    }
    
    printf("%d",count);
}

int main()
{
    int n;
    scanf("%d",&n);
    a[0]=3; 
    func(n);
}