View Code of Problem 3929

#include<stdio.h>
int main()
{
	int t,n,a,sum;
	scanf("%d",&t);
	while(t--)
	{
		sum=0;
		scanf("%d",&n);
		for(int i=0;i<n;i++)
		{
			scanf("%d",&a);
			sum^=a;
		}
		printf("%d\n",sum);
	}
}