View Code of Problem 3929

#include<iostream>
#include<math.h>
#include<string.h>
using namespace std;
int main(){
  	int T;
  	cin>>T;
  	while(T--){
  		int n;
  		cin>>n;
  		long long num;
  		long long sum=0;
  		for(int i=0;i<n;i++){
  			cin>>num;
  			sum^=num;
		  }
		cout<<sum<<endl;
	  }
}