66分求助

jwsdy @ 2023-09-15 17:12:43

#include<bits/stdc++.h>
using namespace std;
int a,b;
bool ss(int s){
    if(s<=1)
    return false;
    for(int i=2;i<=sqrt(s);i++){
        if(s%i==0)
        return false;
    }
    return true;
}
bool huiwen(int s){
    int x[20];
    memset(x,0,sizeof(x));
    int n=0;
    while(s!=0){
        x[++n]=s%10;
        s/=10;
    }
    for(int i=1;i<=n;i++)
    if(x[i]!=x[n-i+1]) return false;
    return true;
}
int main(){
    ios::sync_with_stdio(false);
    cin>>a>>b;
    if(a%2==0) a++;
    for(int i=a;i<=b;i+=2){
        if(ss(i)&&huiwen(i))
        cout<<i<<endl;
    }
    return 0;
}

by w102 @ 2023-09-15 18:08:30

#include<bits/stdc++.h>
using namespace std;
int a,b;
bool ss(int s){
    if(s<=1)
    return false;
    for(int i=2;i<=sqrt(s);i++){
        if(s%i==0)
        return false;
    }
    return true;
}
bool huiwen(int x){
    int n=x,a[20],k=0;
    while(n!=0){
        a[k++]=n%10;
        n/=10;
    }
    for(int i=1;i<k;i++){
        if(a[i]!=a[k-1-i]) return false;
    }
    return true;
}
int main(){
    ios::sync_with_stdio(false);
    cin>>a>>b;
    if(a%2==0) a++;
    for(int i=a;i<=b;i+=2){
        if(huiwen(i)){
            if(ss(i)){
                cout<<i<<endl;
            }
        }
    }
    return 0;
}

回文数判断太麻烦，循环里先判断回文再判断素数，开了02能过