Introduction

In this blog post, we will explore how to solve the LeetCode problem "169" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, 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

Given an array nums of size n, return the majority element. The majority element is the element that appears more than ⌊n / 2⌋ times. You may assume that the majority element always exists in the array. Example 1: Input: nums = [3,2,3] Output: 3 Example 2: Input: nums = [2,2,1,1,1,2,2] Output: 2 Constraints: n == nums.length 1 <= n <= 5 * 104 -109 <= nums[i] <= 109 Follow-up: Could you solve the problem in linear time and in O(1) space?

Explanation

• Boyer-Moore Voting Algorithm: This algorithm cancels out elements that are not the majority element. We maintain a candidate and a count. If the current element is the same as the candidate, we increment the count; otherwise, we decrement it. If the count becomes zero, we choose a new candidate.
  • Linear Scan: The algorithm iterates through the array only once, making it efficient.
  • Guaranteed Majority: Since the problem states that a majority element always exists, the final candidate will be the majority element.

• Time Complexity: O(n), Space Complexity: O(1)

Code

    def majorityElement(nums):
    """
    Finds the majority element in an array using Boyer-Moore Voting Algorithm.

    Args:
        nums: A list of integers.

    Returns:
        The majority element in the array.
    """
    candidate = 0
    count = 0

    for num in nums:
        if count == 0:
            candidate = num
        if num == candidate:
            count += 1
        else:
            count -= 1

    return candidate