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- Prepare
- Algorithms
- Bit Manipulation
- Lonely Integer

# Lonely Integer

# Lonely Integer

Given an array of integers, where all elements but one occur twice, find the unique element.

**Example**

The unique element is .

**Function Description**

Complete the *lonelyinteger* function in the editor below.

lonelyinteger has the following parameter(s):

*int a[n]*: an array of integers

**Returns**

*int:*the element that occurs only once

**Input Format**

The first line contains a single integer, , the number of integers in the array.

The second line contains space-separated integers that describe the values in .

**Constraints**

- It is guaranteed that is an odd number and that there is one unique element.
- , where .

**Sample Input 0**

```
1
1
```

**Sample Output 0**

```
1
```

**Explanation 0**

There is only one element in the array, thus it is unique.

**Sample Input 1**

```
3
1 1 2
```

**Sample Output 1**

```
2
```

**Explanation 1**

We have two 's, and is unique.

**Sample Input 2**

```
5
0 0 1 2 1
```

**Sample Output 2**

```
2
```

**Explanation 2**

We have two 's, two 's, and one . is unique.