XOR Queries of a Subarray

Can you solve this real interview question? XOR Queries of a Subarray - You are given an array arr of positive integers. You are also given the array queries where queries[i] = [lefti, righti].

For each query i compute the XOR of elements from lefti to righti (that is, arr[lefti] XOR arr[lefti + 1] XOR ... XOR arr[righti] ).

Return an array answer where answer[i] is the answer to the ith query.

 

Example 1:

Input: arr = [1,3,4,8], queries = [[0,1],[1,2],[0,3],[3,3]] Output: [2,7,14,8] Explanation: The binary representation of the elements in the array are: 1 = 0001 3 = 0011 4 = 0100 8 = 1000 The XOR values for queries are: [0,1] = 1 xor 3 = 2 [1,2] = 3 xor 4 = 7 [0,3] = 1 xor 3 xor 4 xor 8 = 14 [3,3] = 8

Example 2:

Input: arr = [4,8,2,10], queries = [[2,3],[1,3],[0,0],[0,3]] Output: [8,0,4,4]

Solution

class Solution:
    def xorQueries(self, arr: List[int], queries: List[List[int]]) -> List[int]:
        arr[:]=accumulate(arr, xor)
        ans=[0]*len(queries)
        for i, (q0, qN) in enumerate(queries):
            if q0==0:
                ans[i]=arr[qN]
            else:
                ans[i]=arr[qN]^arr[q0-1]
        return ans