不会高精度，求修改T_T

liruizhou_lihui @ 2023-10-17 20:10:18

#include<bits/stdc++.h>
using namespace std;
bool judgement_prime_number(long long x)
{
    if(x<=1)return 0;
    for(long long i=2;i<sqrt(x);i++)
    {
        if(x%i==0)return 0;
    }
    return 1;
}
bool judgement_Palindromes(long long y)
{
    long long judgement=0;
    long long y2=y;
    while(y2!=0)
    {
        judgement=judgement*10+y2%10;
        y2/=10;
    }
    if(judgement==y)return 1;
    return 0;
}
bool Palindromes_AND_prime(long long x) 
{
    if(judgement_prime_number(x) && judgement_Palindromes(x))return 1;
    return 0;
}
int main()
{
    long long n,m;
    cin>>n>>m;
    for(long long i=n;i<=m;i++)
    {
        if(Palindromes_AND_prime(i))cout<<i<<endl;
    }
    return 0; 
}

by wanglongye @ 2023-10-21 17:27:59

#include<bits/stdc++.h>
using namespace std;
bool judgement_prime_number(long long x)
{
    if(x<=1)return 0;
    for(long long i=2;i<=sqrt(x);i++)//不要漏了i正好等于sqrt(x)的情况 
    {
        if(x%i==0)return 0;
    }
    return 1;
}
bool judgement_Palindromes(long long y)
{
    long long judgement=0;
    long long y2=y;
    while(y2!=0)
    {
        judgement=judgement*10+y2%10;
        y2/=10;
    }
    if(judgement==y)return 1;
    return 0;
}
bool Palindromes_AND_prime(long long x) 
{
    if(judgement_Palindromes(x)&&judgement_prime_number(x))return 1;//先判断回文再判断素数速度更快 
    return 0;
}
int main()
{
    long long n,m,l=10000000;
    cin>>n>>m;
    if (n % 2 == 0) n++;
    for(long long i=n;i<=min(m,l);i += 2)//（这里是不是只看奇数无所谓了）最大的一个不超过10000000（看了题解才知道：偶数位的回文数都是11的倍数） 
    {
        if(Palindromes_AND_prime(i))cout<<i<<endl;
    }
    return 0; 
}

(不一定改对了，你运行一下看一看）