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Solution: Count Triplets That Can Form Two Arrays of Equal XOR

Understand how to count triplets (i, j, k) in an integer array where the XOR of two subarrays are equal. Explore optimizing the naive cubic approach to an O(n) solution using prefix XOR techniques and hash maps. This lesson equips you to apply bitwise manipulation skills to solve this pattern efficiently in coding interviews.

Statement

Given an array of integers, arr, we need to find three indices, i, j, and k, such that 00\leq i << j \leq k << arr.length.

We define two values, a and b, as follows:

  • a = arr[i] ^ arr[i + 1] ^ ... ^ arr[j - 1]

  • b = arr[j] ^ arr[j + 1] ^ ... ^ arr[k]

Note: ^ denotes the bitwise XOR operation.

Return the count of triplets (i, j, k) for which a is equal to b.

Constraints:

  • 11 \leq arr.length 300\leq 300

  • 11 \leq ...