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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3.  
  4. void solve() {
  5.     int n; long long k;
  6.     cin>>n>>k;
  7.  
  8.     vector<long long> a(n+1);
  9.     for(int i=1;i<=n;i++) cin>>a[i];
  10.     unordered_map<long long,long long> mp;
  11.     mp[0]=1;
  12.  
  13.     long long sum=0,ans=0;
  14.     for(int i=1;i<=n;i++) {
  15.         sum+=a[i];
  16.         long long x=((sum-i)%k+k)%k;
  17.         ans+=mp[x];
  18.         mp[x]++;
  19.     }
  20.     cout<<ans<<'\n';
  21. }
  22.  
  23. int main() {
  24.     ios_base::sync_with_stdio(false);
  25.     cin.tie(NULL);
  26.  
  27.     int t; cin>>t;
  28.     while(t--) solve();
  29. }
Success #stdin #stdout 0.01s 5284KB
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https://ideone.com/hutBDG
23 part 2
language:
C++14 (gcc 8.3)
created:
9 hours ago
visibility:
public

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