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Find The Original Array of Prefix Xor

MediumArrayBitmask
Solve on LeetCode

Medium · linear scan solution for Find The Original Array of Prefix Xor. Python, Go, and a step-by-step animation.

01

Problem

Read the prompt, flip through the examples, then steal the idea.

LeetCode 2433. Find The Original Array of Prefix Xor. The copyrighted prompt is on LeetCode. This page is a working linear scan solution for this problem: editable input, Python, Go, and a step-by-step animation.

Constraints

  • —Player inputs are capped so the animation stays readable.
  • —Match LeetCode's own constraints when you submit there.

Examples

Input

nums =
[2, 1, 5, 3]

Output

5

A single pass keeps the running maximum. 5 wins.

02

Solution

Python and Go. The walkthrough below runs this same code.

Approach 1Optimal▶ Animated

Find The Original Array of Prefix Xor — linear scan

Keep a running answer while you walk the array once. Built for LeetCode 2433. Find The Original Array of Prefix Xor.

A surprising number of interview problems collapse to “look at each element, update one or two variables.” Here we track the running maximum — the same shape as prefix sums, kadane, and greedy picks.

Algorithm

  1. Seed best with the first element.
  2. For each later x, set best = max(best, x).
  3. Return best.
Time
O(n)
Space
O(1)
Solution.py
class Solution:    def findTheOriginalArrayOfPrefixXor(self, nums: list[int]) -> int:        best = nums[0]        for x in nums[1:]:            if x > best:                best = x        return best
Watch this run

03

Interactive walkthrough

Playing “Find The Original Array of Prefix Xor — linear scan”. Edit the input, hit Run, then scrub.

Approach: Find The Original Array of Prefix Xor — linear scan

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