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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3. #define FIO ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
  4. #define mod 1000000007
  5. #define test ll t; cin>>t; while(t--)
  6. typedef long long int ll;
  7. bool check(ll k,ll a[],ll n){
  8.     ll b[n];
  9.     ll i;
  10.     for(i=0;i<n;i++){
  11.         b[i]=a[i]^k;
  12.     }
  13.     // Checking
  14.     ll s[2050];
  15.     for(i=0;i<2050;i++){
  16.         s[i]=0;
  17.     }
  18.     for(i=0;i<n;i++){
  19.         s[a[i]]++;
  20.         s[b[i]]--;
  21.     }
  22.     for(i=0;i<2050;i++){
  23.         if(s[i]!=0){
  24.             return false;
  25.         }
  26.     }
  27.     return true;
  28. }
  29. int main() {
  30.     FIO;
  31.     test{ // 1000
  32.         ll n,i,x,flag=0;
  33.         cin>>n;
  34.         ll a[n];
  35.         for(i=0;i<n;i++){
  36.             cin>>a[i];
  37.         }
  38.         for(i=1;i<=1024;i++){ // 1000 * 1024
  39.             bool res=check(i,a,n); // 1000 * 1024 * 2050
  40.             if(res==true){
  41.                 cout<<i<<endl;
  42.                 flag=1;
  43.                 i=1034;
  44.             }
  45.         }
  46.         if(flag==0){
  47.             cout<<-1<<endl;
  48.         }
  49.     }
  50. 	return 0;
  51. }
  52.  
Runtime error #stdin #stdout 0s 4384KB
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Standard input is empty
stdout
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Standard output is empty
https://ideone.com/0XrYUt
language:
C++14 (gcc 8.3)
created:
3 years ago
visibility:
secret

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