# 1442. Count Triplets That Can Form Two Arrays of Equal XOR

https://leetcode.com/problems/count-triplets-that-can-form-two-arrays-of-equal-xor

## Description

Given an array of integers `arr`.

We want to select three indices `i`, `j` and `k` where `(0 <= i < j <= k < arr.length)`.

Let's define `a` and `b` as follows:

* `a = arr[i] ^ arr[i + 1] ^ ... ^ arr[j - 1]`
* `b = arr[j] ^ arr[j + 1] ^ ... ^ arr[k]`

Note that **^** denotes the **bitwise-xor** operation.

Return _the number of triplets_ (`i`, `j` and `k`) Where `a == b`.

**Example 1:**

```

**Input:** arr = [2,3,1,6,7]
**Output:** 4
**Explanation:** The triplets are (0,1,2), (0,2,2), (2,3,4) and (2,4,4)
```

**Example 2:**

```

**Input:** arr = [1,1,1,1,1]
**Output:** 10
```

**Example 3:**

```

**Input:** arr = [2,3]
**Output:** 0
```

**Example 4:**

```

**Input:** arr = [1,3,5,7,9]
**Output:** 3
```

**Example 5:**

```

**Input:** arr = [7,11,12,9,5,2,7,17,22]
**Output:** 8
```

**Constraints:**

* `1 <= arr.length <= 300`
* `1 <= arr[i] <= 10^8`

## ac

```java
```
