LeetCode-in-All

169. Majority Element

Easy

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
• -231 <= nums[i] <= 231 - 1

Follow-up: Could you solve the problem in linear time and in O(1) space?

Solution

# @param {Integer[]} nums
# @return {Integer}
def majority_element(nums)
  candidate_count = 0
  candidate_letter = nil

  nums.each_with_object({}) do |num, hash|
    hash[num] = 1 + hash[num] ||= 0
  end.each do |k, v|
    next if candidate_count >= v

    candidate_letter = k
    candidate_count = v
  end

  candidate_letter
end

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