@[IAKIOI66666](/user/1343308) 我的代码:
```cpp
#include<bits/stdc++.h>
using namespace std;
int l, r;
bool weishu(int x)//位数
{
if((1000 <= x && x <= 9999) || (100000 <= x && x <= 999999)) return 0;
return 1;
}
bool huiwen(int x)//回文
{
int a[20], flag = 1;
while (x > 0)
{
a[flag] = x % 10;
x /= 10;
flag++;
}
for (int i = 1; i <= flag / 2; i++)
if(a[i] != a[flag-i]) return 0;
return 1;
}
bool zhishu(int x)//质数
{
if(x == 2) return 1;
for(int i = 2; i <= sqrt(x); i++)
if(x % i == 0) return 0;
return 1;
}
int main(){
// freopen("1.in","r",stdin);
// freopen("1.out","w",stdout);
cin>>l>>r;
if(l == 2) printf("2\n");
if(l % 2 == 0) l++;
r = min(9999999, r);
for(int i = l; i <= r; i = i + 2)
{
if(weishu(i) == 0) continue;
if(huiwen(i) == 0) continue;
if(zhishu(i) == 0) continue;
cout<<i<<endl;
}
return 0;
}
```
可以提前排除一些情况,减少筛选的时间和次数
by GXZJQ @ 2024-04-24 21:16:50
谢谢大佬！
by IAKIOI66666 @ 2024-04-24 21:18:31