Submission #3011578

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Source Code Expand

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <queue>
#include <string>
#include <set>
#include <map>
#define REP(i,n) for(ll i = 0; i < (ll)n; i++)
#define INF 1000000000000000
using namespace std;
typedef long long ll;
typedef double db;
typedef string str;

vector<bool> sieve(ll n){
  vector<bool> is_prime(n+1);
  fill(is_prime.begin(),is_prime.end(),true);
  for(ll i = 0; i<=n; i++) is_prime[i] = true;
  is_prime[0] = is_prime[1] = false;
  for(ll i=2; i<=n; i++){
    if(is_prime[i]){
      for(ll j = 2*i; j<=n; j+=i){
        is_prime[j] = false;
      }
    }
  }
  return is_prime;
}

int main(){
  vector<bool> is_prime = sieve(100000);
  ll cnt[100001];
  cnt[0] = 0;
  for(ll i = 1; i <= 100000; i++){
    if(is_prime[i] == true&&is_prime[(i+1)/2]==true){
      cnt[i] = cnt[i-1]+1;
    }else{
      cnt[i] = cnt[i-1];
    }
  }
  ll q;
  cin >> q;
  REP(i,q){
    ll l,r;
    cin >> l >> r;
    cout << cnt[r]-cnt[l-1] << endl;
  }
  return 0;
}

Submission Info

Judge Result