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  1. #include <iostream>
  2. #include <bits/stdc++.h>
  3. #include <math.h>
  4. using namespace std;
  5.  
  6.  
  7. int solve(vector<int>A,int k,int p){
  8.     int n=A.size();
  9.     int cnt=0;
  10.     unordered_map<int,int>mpp;
  11.     for(int i=0;i<n;i++){
  12.         int x=A[i];
  13.         int val=pow(x,4);
  14.         int required=(val%p)-((k*x)%p)+p;
  15.         required=required%p;
  16.         cnt+=mpp[required];
  17.  
  18.         mpp[required]++;
  19.     }
  20.     return cnt;
  21. }
  22.  
  23. int main(){
  24.     int n;
  25.     cin>>n;
  26.     vector<int>A(n);
  27.     for(int i=0;i<n;i++){
  28.         cin>>A[i];
  29.     }
  30.  
  31.     int k,p;
  32.     cin>>k>>p;
  33.     int number_of_pairs=solve(A,k,p);
  34.     cout<<"Number of pairs that are valid: "<<number_of_pairs<<endl;
  35.     return 0;
  36. }
Success #stdin #stdout 0s 5320KB
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stdout
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Number of pairs that are valid: 1
https://ideone.com/GCb1Zc
language:
C++ (gcc 8.3)
created:
16 hours ago
visibility:
public

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