55pts求调

P1217 [USACO1.5] 回文质数 Prime Palindromes

hzoi_Shadow @ 2023-04-16 11:04:23


#include<bits/stdc++.h>
using namespace std;
bool isprime(int x)
{
    int i;
    for(i=3;i<=sqrt(x);i+=2)
    {
        if(x%i==0) 
        {
            return false;
        }
    } 
    return true;
}
bool huiwen(int n)
{
    int num=0,sum=0,cnt=n;
    while(cnt>0)
    {
        num++;
        cnt/=10;
    }
    cnt=n;
    if(num%2==1)
    {
        while(cnt>0)
        {
            sum*=10;
            sum+=cnt%10;
            cnt/=10;
        }
        if(sum==n)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    else
    {
        return false;
    }
}
int main()
{
    int a,b,ans=0,i;
    cin>>a>>b;
    if(a<=2)
    {
        printf("2\n");
    }
    if(a%2==0)
    {
        a++;
    }
    for(i=a;i<=b;i+=2)
    {
        if(isprime(i)==true&&huiwen(i)==true)
        {
            printf("%d\n",i);
        }
    }
    return 0;
}

by hzoi_Shadow @ 2023-04-16 11:25:20

这是目前的,66pts,T了最后三个点


#include<bits/stdc++.h>
using namespace std;
bool isprime(int x)
{
    int i;
    if(x==1)
    {
        return false;
    }
    else
    {
        for(i=3;i<=sqrt(x);i+=2)
        {
            if(x%i==0) 
            {
                return false;
            }
        } 
        return true;
    }
}
bool huiwen(int n)
{
    int num=0,sum=0,cnt=n;
    while(cnt>0)
    {
        num++;
        sum*=10;
        sum+=cnt%10;
        cnt/=10;
    }
    if((num==2||num%2==1)&&sum==n)
    {
        return true;
    } 
    else
    {
        return false;
    } 
}
int main()
{
    int a,b,i;
    cin>>a>>b;
    if(a<=2)
    {
        printf("2\n");
    }
    if(a%2==0)
    {
        a++;
    }
    for(i=a;i<=b;i+=2)
    {
        if(isprime(i)==true&&huiwen(i)==true)
        {
            printf("%d\n",i);
        }
    }
    return 0;
}

by wkh2008 @ 2023-04-16 11:27:12

@The_Shadow_Dragon 但凡看看提示


by hzoi_Shadow @ 2023-04-16 11:27:49

@wkh2008 az


by hzoi_Shadow @ 2023-04-16 11:37:35

@wkh2008 换了个顺序AC了


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