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

function countTriplets(arr: number[]): number {
    const n = arr.length
    let count = 0
    const prefixXOR: number[] = new Array(n + 1).fill(0)

    for (let i = 0; i < n; i++) {
        prefixXOR[i + 1] = prefixXOR[i] ^ arr[i]
    }

    for (let i = 0; i < n; i++) {
        for (let k = i + 1; k < n; k++) {
            if (prefixXOR[i] == prefixXOR[k + 1]) {
                count += (k - i)
            }
        }
    }

    return count

}