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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3. #define ll long long 
  4. #define maxn 200005
  5. #define maxm 10000005
  6. ll mapping[2*maxm];
  7. ll a[maxn];
  8. map<ll,ll> dau;
  9. vector<ll> z;
  10. ll n;
  11. ll f[7]={1,11,111,1111,11111,111111,1111111};
  12. void init(){
  13.     for(ll i=1;i<=9;i++){
  14.        for(ll j=0;j<7;j++) z.push_back(i*f[j]);
  15.    }
  16. }
  17. int main(){
  18.     // freopen("lala.out","w",stdout);
  19.     ios_base::sync_with_stdio(false);
  20.     cin.tie(NULL);
  21.    init();
  22.     cin>>n;
  23.     ll x;
  24.     for(ll i=0;i<n;i++){
  25.         cin>>x;
  26.         a[i]=x;
  27.         mapping[x]++;
  28.     }
  29.     ll ans=0;
  30.     for (ll u=0;u<63;u++){
  31.            ll summa = z[u];
  32.         for(ll i=0;i<n;i++){
  33.             if(summa-a[i]<0) continue;
  34.             ans = ans + mapping[summa-a[i]];
  35.             if(summa-a[i]==a[i]) ans--;
  36.         }
  37.     }
  38.     ans/=2;
  39.     cout<<ans;
  40.  
  41.    return 0;
  42. }
Success #stdin #stdout 0s 4968KB
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https://ideone.com/AJQYhf
language:
C++ (gcc 8.3)
created:
3 years ago
visibility:
public

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