HTMLify

class Solution:
    def subarrayXor(self, arr, k):
        res = 0
        pref_xor = 0
        counts = {0: 1}
        
        for val in arr:
            pref_xor ^= val
            
            target = pref_xor ^ k
            if target in counts:
                res += counts[target]
            
            counts[pref_xor] = counts.get(pref_xor, 0) + 1
            
        return res