分析：暴力枚举1-8位数，并判断是否为素数
1 /* 2 PROB:pprime 3 ID:wanghan 4 LANG:C++ 5 */ 6 #include "iostream" 7 #include "cstdio" 8 #include "cstring" 9 #include "string" 10 #include "vector" 11 #include "algorithm" 12 using namespace std; 13 vector<int> h; 14 int a,b; 15 bool judge(int x){ 16 if(x<=2) 17 return false; 18 for(int i=2;i*i<=x;i++) 19 if(x%i==0) 20 return false; 21 return true; 22 } 23 void solve12(){ //1 2 24 for(int i=0;i<=9;i++){ 25 int num1=i; 26 int num2=i*10+i; 27 if(judge(num1)) h.push_back(num1); 28 if(judge(num2)) h.push_back(num2); 29 } 30 } 31 void solve34(){ //3 4 32 for(int i=0;i<=9;i++){ 33 for(int j=0;j<=9;j++){ 34 int num3=100*i+10*j+i; 35 int num4=1000*i+100*j+10*j+i; 36 if(judge(num3)) h.push_back(num3); 37 if(judge(num4)) h.push_back(num4); 38 } 39 } 40 } 41 void solve56(){ //7 8 42 for(int i=0;i<=9;i++){ 43 for(int j=0;j<=9;j++){ 44 for(int k=0;k<=9;k++){ 45 int num5=10000*i+1000*j+100*k+10*j+i; 46 int num6=100000*i+10000*j+1000*k+100*k+10*j+i; 47 if(judge(num5)) h.push_back(num5); 48 if(judge(num6)) h.push_back(num6); 49 } 50 } 51 } 52 } 53 void solve78(){ 54 for(int i=0;i<=9;i++){ 55 for(int j=0;j<=9;j++){ 56 for(int k=0;k<=9;k++){ 57 for(int f=0;f<=9;f++){ 58 int num7=1000000*i+100000*j+10000*k+1000*f+100*k+10*j+i; 59 int num8=10000000*i+1000000*j+100000*k+10000*f+1000*f+100*k+10*j+i; 60 if(judge(num7)) h.push_back(num7); 61 if(judge(num8)) h.push_back(num8); 62 } 63 } 64 } 65 } 66 } 67 int main() 68 { 69 freopen("pprime.in","r",stdin); 70 freopen("pprime.out","w",stdout); 71 cin>>a>>b; 72 solve12(); solve34();solve56();solve78(); 73 sort(h.begin(),h.end()); 74 int len=h.size(); 75 for(int i=0;i<len;i++){ 76 if(h[i]>=a&&h[i]<=b) 77 cout<<h[i]<<endl; 78 } 79 return 0; 80 }