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  1. #include <bits/stdc++.h>
  2. #define ll long long int
  3.  
  4. using namespace std;
  5.  
  6. ll t,num,f,mx=4294967296;
  7. bool prime[100000];
  8. vector <int> prv;
  9.  
  10. void seive()
  11. {
  12.     memset(prime,true,sizeof(prime));
  13.     int n=sqrt(100000),sum=2;
  14.     while(sum+2<=100000){
  15.         prime[sum+2]=false;
  16.         sum+=2;
  17.     }
  18.  
  19.     for(int i=3;i<=n;i++){
  20.         if(prime[i]!=false){
  21.             for(int j=2*i;j<=100000;j=j+i){
  22.                 prime[j]=false;
  23.             }
  24.         }
  25.     }
  26.     for(int i=2;i<=100000;i++){
  27.         if(prime[i]==true){
  28.             prv.push_back(i);
  29.         }
  30.     }
  31. }
  32.  
  33. int main()
  34. {
  35.     seive();
  36.     cin>> t;
  37.     for(int x=1;x<=t;x++){
  38.         cin>> num;
  39.         f=1,num=num-1;
  40.         for(int i=num;i>=0;i--){
  41.              f=0;
  42.             for(int j=0;prv[j]*prv[j]<=i;j++){
  43.                 if(i%prv[j]==0){
  44.                     f=1;
  45.                     break;
  46.                 }
  47.                 else{
  48.                     f=0;
  49.                 }
  50.             }
  51.             if(f==0){
  52.                 cout<< i << endl;
  53.                 break;
  54.             }
  55.         }
  56.  
  57.     }
  58.     return 0;
  59. }
  60.  
Success #stdin #stdout 0s 3564KB
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https://ideone.com/0j58Ej
language:
C++14 (clang 8.0)
created:
7 years ago
visibility:
public

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