求助

Libingyue2011 @ 2022-12-31 12:17:43

#include<bits/stdc++.h>
using namespace std;
bool prime(int x){
    if(x==1) return 0;
    for(int i=2;i*i<=x;i++){
        if(x%i==0) return 0;
    } 
    return 1;
}
int m,n;
bool f(int x){
    return (x>=m)&&(x<=n);
}
int main() {
    scanf("%d %d",&m,&n); 
    for(int i=5;i<=9;i+=2){//一位数 
        if(f(i)==1&&prime(i)==1) printf("%d\n",i);
    }
    if(f(11)==1) printf("11\n");//两位数
    for(int i=1;i<=9;i+=2){//三位数 
        for(int j=0;j<=9;j++){
            if(f(101*i+10*j)==1&&prime(101*i+10*j)==1) printf("%d\n",101*i+10*j);
        }
    }
    for(int i=1;i<=9;i+=2){//四位数 
        for(int j=1;j<=9;j++){
            if(f(1001*i+110*j)==1&&prime(1001*i+10*j)==1) printf("%d\n",1001*i+10*j);
        }
    }
    for(int i=1;i<=9;i+=2){//五位数 
        for(int j=0;j<=9;j++){
            for(int k=0;k<=9;k++){
                if(f(10001*i+1010*j+100*k)==1&&prime(10001*i+1010*j+100*k)==1)
                    printf("%d\n",10001*i+1010*j+100*k);
            }
        }
    }
    for(int i=1;i<=9;i+=2){//六位数 
        for(int j=0;j<=9;j++){
            for(int k=0;k<=9;k++){
                if(f(100001*i+1001*j+11*k)==1&&prime(100001*i+1001*j+11*k)==1)
                    printf("%d\n",100001*i+1001*j+11*k);
            }
        }
    }
    for(int i=1;i<=9;i+=2){//七位数 
        for(int j=0;j<=9;j++){
            for(int k=0;k<=9;k++){
                for(int l=0;l<=9;l++){
                    if(f(1000001*i+100010*j+10100*k+1000*l)==1&&prime(1000001*i+100010*j+10100*k+1000*l)==1)
                        printf("%d\n",1000001*i+100010*j+10100*k+1000*l);
                }
            }
        }
    }
    for(int i=1;i<=9;i+=2){//八位数 
        for(int j=0;j<=9;j++){
            for(int k=0;k<=9;k++){
                for(int l=0;l<=9;l++){
                    if(f(10000001*i+1000010*j+100100*k+11000*l)==1&&prime(10000001*i+1000010*j+100100*k+11000*l)==1)
                        printf("%d\n",10000001*i+1000010*j+100100*k+11000*l);
                }
            } 
        }
    }
    return 0;
} 

by Libingyue2011 @ 2022-12-31 12:18:19

没有 TLE 哟

by _Peter_ @ 2022-12-31 14:08:02

#include <iostream>
#include <cmath>

using namespace std;

bool isZhiShu( int x ){
    bool f = true;
    int sqrtx=sqrt(x);
    for( int i = 2 ; i <= sqrtx ; i++ ){
        if( x % i == 0 ){
            f = false;
            return false;
        }
    }
    return true;
}

bool isHuiWen( int x ){
    int x_old = x, sum = 0, xj = x;
    //把x反过来,判断x是否与之前的x一样
    while( x_old != 0 ){
        x = x_old;
        x %= 10;
        sum = (sum + x ) * 10;
        x_old /= 10;
    }
    sum /= 10;
    if( sum == xj ){
        return true;
    }
    return false;
}

int main()
{
    int a, b;
    cin >> a >> b;
    if( a % 2 == 0 ){
        a++;
    } 
    for( int i = a ; i <= b ; i += 2 ){
        if( isHuiWen(i) && isZhiShu(i) ){
            cout << i << endl;
        }
    }
    return 0;
}

by Lucas2024 @ 2023-01-25 15:50:25

#include<iostream>
#include<cmath>
using namespace std;
int m,n,pal[100000005],pos=4;
bool isprime(int x)
{
    int i;
    for(i=2;i<=sqrt(x);i++)
    {
        if(x%i==0)
        {
            return false;
            break;
        }       
    }
    return true;
}
int main()
{
    int a,b,c,d,e,i;
    cin>>m>>n;

    pal[1]=5;pal[2]=7;pal[3]=11;
    for(a=1;a<=9;a+=2)/*只有奇数是素数*/
    {
        for(b=0;b<=9;b++)
        {
            pal[pos++]=101*a+10*b;
        }       
    }//三位
    for(a=1;a<=9;a+=2)
    {
        for(b=0;b<=9;b++)
        {
            for(c=0;c<=9;c++)
            {
                pal[pos++]=10001*a+1010*b+100*c;
            }
        }
    }//五位
    for(a=1;a<=9;a+=2)
    {
        for(b=0;b<=9;b++)
        {
            for(c=0;c<=9;c++)
            {
                for(d=0;d<=9;d++)
                {
                    pal[pos++]=1000001*a+100010*b+10100*c+1000*d;
                }
            }
        }
    }//七位
    for(a=1;a<=9;a+=2)
    {
        for(b=0;b<=9;b++)
        {
            for(c=0;c<=9;c++)
            {
                for(d=0;d<=9;d++)
                {
                    for(e=0;e<=9;e++)
                    {
                        pal[pos++]=100000001*a+10000010*b+1000100*c+101000*d+10000*e;
                    }
                }               
            }
        }
    }//九位
   /*构造回文数*/
    for(i=1;pal[i]<=n;i++)
    {
        if(pal[i]>=m&&isprime(pal[i]))
        {
            cout<<pal[i]<<endl;
        }
    }
    return 0;
}