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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. const int MOD =(int)1e9+7;
  5.  
  6. long long modpow(long long a,long long e = MOD - 2) {
  7.     long long r = 1;
  8.     while (e) {
  9.         if (e & 1) r = r*a%MOD;
  10.         a = a*a % MOD;
  11.         e >>= 1;
  12.     }
  13.     return r;
  14. }
  15.  
  16. int main() {
  17.     int N;
  18.     if (!(cin >> N))
  19.       return 0;
  20.  
  21.     vector<int> A(N);
  22.     int maxA = 0;
  23.     for (int i = 0;i<N;i++) 
  24.     { cin >> A[i];
  25.     maxA = max(maxA,A[i]);
  26.     }
  27.  
  28.     vector<int> freq(maxA+1,0);
  29.     for (int x:A) freq[x]++;
  30.  
  31.     vector<int> is_composite(maxA+1,0), primes;
  32.     for (int i =2;i*i<=maxA;i++) {
  33.         if (is_composite[i] == 0) {
  34.             for (int j = i*i; j<=maxA; j+=i) 
  35.              is_composite[j] = 1;
  36.         }
  37.     }
  38.     for (int i =2;i<= maxA;i++) 
  39.      if (is_composite[i] == 0)
  40.       primes.push_back(i);
  41.  
  42.     vector<int> cnt = freq;
  43.     for (int p:primes)
  44.         for (int i =1;i<=maxA/p;i++)
  45.             cnt[i] += cnt[i*p];
  46.  
  47.     vector<long long> fact(N+1,1),invfact(N+1,1);
  48.     for (int i = 1; i <= N; i++) 
  49.       fact[i] = fact[i - 1]*i%MOD;
  50.     invfact[N] = modpow(fact[N]);
  51.     for (int i = N; i >= 1; i--)
  52.      invfact[i - 1] = invfact[i]*i%MOD;
  53.     auto C = [&](int n, int k)->long long{
  54.         if (k < 0 || k > n) return 0;
  55.         return fact[n]*invfact[k]%MOD*invfact[n - k]%MOD;
  56.     };
  57.  
  58.     int Q;
  59.     cin>>Q;
  60.     struct Query {int g,idx;};
  61.     unordered_map<int, vector<Query>> bucket;
  62.     bucket.reserve(Q*2);
  63.     vector<long long> answer(Q);
  64.  
  65.     for (int i =0;i<Q;i++) {
  66.         int k,g; 
  67.         cin>>k>> g;
  68.         bucket[k].push_back({g, i});
  69.     }
  70.  
  71.     vector<long long> S(maxA + 1), E(maxA + 1);
  72.  
  73.     for (auto &entry :bucket) {
  74.         int k = entry.first;
  75.         auto &qs = entry.second;
  76.         for (int d =1;d <= maxA;d++) 
  77.          S[d] = C(cnt[d], k);
  78.         E = S;
  79.         for (int p:primes)
  80.             for (int i =1;i<= maxA/p;i++) {
  81.                 E[i]-= E[i * p];
  82.                 if (E[i]<0) E[i]+=MOD;
  83.             }
  84.         for (int d=1;d<=maxA;d++) {
  85.             E[d]%=MOD;
  86.             if (E[d]<0)
  87.               E[d]+=MOD;
  88.         }
  89.         for (auto &q:qs) {
  90.             int g =q.g;
  91.             answer[q.idx] = (g<=maxA?E[g]:0);
  92.         }
  93.     }
  94.  
  95.     for (int i=0;i<Q;i++) 
  96.      cout <<answer[i]%MOD<< '\n';
  97.     return 0;
  98. }
  99.  
Success #stdin #stdout 0.01s 5284KB
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https://ideone.com/rV7O51
language:
C++14 (gcc 8.3)
created:
3 days ago
visibility:
public

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