LEETCODEEasy

Majority Element

풀이일 2025 · 03 · 17기록 3 ms · 58.7 MB원문 leetcode ↗

ArrayHash TableDivide and ConquerSortingCountingBoyer–Moore Majority Vote Algorithm

문제

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
The input is generated such that a majority element will exist in the array.

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

풀이 TypeScript

function majorityElement(nums: number[]): number {
  const occurrences: Record<number, number> = {};
  const majorLength = Math.floor(nums.length / 2);
  for(let i = 0; i < nums.length; i++) {
    occurrences[nums[i]] = (occurrences[nums[i]] || 0) + 1;
    if(occurrences[nums[i]] > majorLength) {
      return nums[i];
    }
  }
  return -1
}

복사됨