#include<algorithm> #include<iostream> #include<vector> using namespace std; int main() { int t; cin>>t; while(t--) { int n; cin>>n; int a[10010]={0},sum=0; vector<int>v; for(int i=0;i<n;i++) { int temp; cin>>temp; a[temp]++; v.push_back(temp); } for(int i=0;i<v.size();i++) { if(a[v[i]]%2==1) sum^=v[i]; } cout<<sum<<endl; } } |
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