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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3.  
  4. #define ll long long
  5.  
  6. int main(){
  7.     ios_base::sync_with_stdio(false);
  8.     cin.tie(NULL);
  9.     int n,k,c=0;
  10.     cin>>n>>k;
  11.     vector<int>v(n),p(n,0);
  12.     for(int i=0;i<n;i++){
  13.         cin>>v[i];
  14.         if(i==0)p[0]=v[0];
  15.         p[i]=p[i-1]+v[i];
  16.     }
  17.     unordered_map<int,int>mp;
  18.     mp[0]=1;
  19.     for(int i=0;i<n;i++){
  20.         if(mp.find((p[i]%k-i%k-v[i]%k+k+1%k)%k)!=mp.end()){
  21.             c+=mp[(p[i]%k-i%k-v[i]%k+k+1%k)%k];
  22.         }
  23.         mp[(p[i]%k-i%k-v[i]%k+k+1%k)%k]++;
  24.     }
  25.     cout<<c<<"\n"; 
  26.     return 0;
  27. }
Success #stdin #stdout 0.01s 5320KB
comments (?)
stdin 
4 4
1 3 2 4
stdout 
2
https://ideone.com/dy9KAj
language:
C++14 (gcc 8.3)
created:
7 days ago
visibility:
public

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