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  1. #include <bits/stdc++.h>
  2. #define FOR(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
  3. #define fi first
  4. #define se second
  5. #define el "\n"
  6. #define pb push_back
  7. #define sz(a) (int)a.size()
  8. #define FILL(a, x) memset(a, x, sizeof(a))
  9.  
  10. using namespace std;
  11. typedef long long ll;
  12. typedef pair<int, int> ii;
  13. const int N = (int)1e6+3, MAX = (int)1e6;
  14. int T;
  15. int P[N];
  16.  
  17. void Sieve(){
  18.    P[1] = 1;
  19.    for(int i = 2; i*i <= MAX; i++)
  20.      if (!P[i])
  21.       for(int j = 2*i; j <= MAX; j += i)
  22.        if (!P[j]) P[j] = i;
  23.    FOR(i, 2, MAX)
  24.     if (!P[i]) P[i] = i;
  25. }
  26.  
  27. bool Check(int x){
  28.     int L, cnt, p;
  29.     L = cnt = p = 0;
  30.     while(x > 1){
  31.         p = P[x];
  32.         cnt = 0;
  33.         while(x%p==0){
  34.             cnt++;
  35.             x /= p;
  36.             if (cnt > 1) return 0;
  37.         }
  38.         L++;
  39.         if (L > 2) return 0;
  40.     }
  41.     return (L == 2);
  42. }
  43.  
  44. int main()
  45. {
  46.     ios_base::sync_with_stdio(false);
  47.     cin.tie(NULL);    cout.tie(NULL);
  48.     freopen("PRIME.inp", "r", stdin);
  49.     freopen("PRIME.out", "w", stdout);
  50.     Sieve();
  51.     cin>>T;
  52.     while(T--){
  53.         int x;
  54.         cin>>x;
  55.         while(!Check(x)) x--;
  56.         cout<<x<<el;
  57.     }
  58.     return 0;
  59. }
  60.  
Success #stdin #stdout 0.01s 7772KB
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https://ideone.com/fvP3MX
language:
C++14 (clang 8.0)
created:
5 days ago
visibility:
public

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