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

Discover how to efficiently count triplets in an array that form two subarrays with equal XOR values. Learn to apply prefix XOR and hash maps to optimize from a naive cubic to a linear time complexity solution using bitwise manipulation.

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 ...