# Solving Leetcode Interviews in Seconds with AI: XOR Queries of a Subarray


	# Introduction
	In this blog post, we will explore how to solve the LeetCode problem "1310" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like [Chatmagic](https://www.chatmagic.app), we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

	# Problem Statement
	> 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]    Constraints:  1 <= arr.length, queries.length <= 3 * 104 1 <= arr[i] <= 109 queries[i].length == 2 0 <= lefti <= righti < arr.length  

	# Explanation
	Here's a breakdown of the approach and the Python code:

*   **Prefix XOR Array:** Create a prefix XOR array where each element `prefix_xor[i]` stores the XOR of all elements from `arr[0]` to `arr[i]`.
*   **Query Calculation:** For each query `[left, right]`, calculate the XOR sum from `left` to `right` using the prefix XOR array. If `left > 0`, the XOR sum is `prefix_xor[right] ^ prefix_xor[left-1]`. If `left == 0`, the XOR sum is simply `prefix_xor[right]`.
*   **Result:** Store the results of each query in an answer array.

*   **Runtime Complexity:** O(n + m), where n is the length of `arr` and m is the number of queries.
*   **Storage Complexity:** O(n)

	
	# Code
	```python
	def xor_queries(arr, queries):
    """
    Calculates the XOR of elements within given ranges in an array.

    Args:
        arr (list of int): An array of positive integers.
        queries (list of list of int): A list of queries, where each query is a list [left, right].

    Returns:
        list of int: An array containing the XOR results for each query.
    """

    prefix_xor = [0] * len(arr)
    prefix_xor[0] = arr[0]

    for i in range(1, len(arr)):
        prefix_xor[i] = prefix_xor[i - 1] ^ arr[i]

    answer = []
    for left, right in queries:
        if left == 0:
            answer.append(prefix_xor[right])
        else:
            answer.append(prefix_xor[right] ^ prefix_xor[left - 1])

    return answer
	```