Bình luận

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  khactrung1308  đã bình luận lúc 20, Tháng 6, 2026, 15:55

  include <bits/stdc++.h>

  using namespace std;

  define nmax 10000010

  define ll long long

  bool nt[nmax]; ll a[nmax]; ll f[nmax]; void sangnt() { for (ll i=0;i<nmax;i++) nt[i]=1; nt[0]=nt[1]=0; for (long long i=2;ii<nmax;i++) { if (nt[i]) { for (long long j=ii;j<nmax;j+=i) nt[j]=0; } } } bool nttd(ll n) { ll k=n; if(!nt[n]) return 0; n/=10; while (n>0) { if(!nt[n]) return 0; n/=10; } for (ll i=0;i<=9;i++) { if (nt[k*10+i]) return 1; } return 0; } int main() { ios::syncwithstdio(false); cin.tie(nullptr); sangnt(); ll n; cin>>n; ll t=0; for(ll i=1;i<=n;i++) { cin>>a[i]; if(nttd(a[i])) t++; f[i]=t; } ll m; cin>>m; while(m--) { ll u,v; cin>>u>>v; cout<<f[v]-f[u-1]<<'\n'; } return 0; }