# Question Name:Element appearing once

```#include <stdio.h>
int main()
{
int a,b,c,d,i,min,k;
scanf("%d",&a);
for(i=0;i<a;i++)
{
scanf("%d",&b);
for(k=0;k<b;k++)
{
scanf("%d",&c[k]);
}
for(k=0;k<b;k++)
{

if(c[k]!=c[k+1] && c[k]!=c[k+2] && c[k]!=c[k-1] && c[k]!=c[k-2] )
{
printf("%d",c[k]);
}
}
printf("\n");
}
return 0;
}```

### Problem Description

Given an sorted array A[i] of N positive integers having all the numbers occuring exactly twice, except for one number which will occur only once. Find the number occuring only once.

Input

The first line of input contains an integer T denoting the number of test cases. Then T test cases follow.

The first line of each test case contains a positive integer N, denoting the size of the array.

The second line of each test case contains a N positive integers, denoting the elements of the array.

Output

Print out the singly occurring number.

Constraints
1 <= T <= 100
0 < N <= 100
0 <= A[i] <= 100

• ###### Test Case 1

Input (stdin)

```2
5
1 1 2 5 5
7
2 2 5 5 20 30 30
```

Expected Output

```2
20```
• ###### Test Case 2

Input (stdin)

```2
5
1 1 2 5 5
3
20 30 30
```

Expected Output

```2
20``` 