Simple majority
Input
majority_element([3, 3, 4])
Output
3
3 appears 2 of 3 times, which is > 3/2, so it's the majority.
Full lesson preview
Find the majority element in an array
Find the element that appears more than half the time using Boyer–Moore Voting Algorithm.
Python practice16 minArrays – Fundamentals & PatternsIntermediateLast updated March 25, 2026
Problem statement
Given a list of integers, find the majority element — an element that appears more than n/2 times in the list. If such an element exists, return it; otherwise return None. Implement an algorithm with O(n) time and O(1) space, and verify the candidate before returning.
Task
Return the majority element (element appearing > n/2 times) if it exists; otherwise return None. Use O(n) time and O(1) extra space.
Examples
Input format
A single list of integers, e.g. [3, 3, 4].
Output format
Return the majority element as an integer if found; otherwise return None (compared as empty output).
Constraints
1 <= len(nums) <= 10^5. Elements are integers. Must run in O(n) time and O(1) extra space.
Samples
Sample 1
Input
[2, 2, 1, 1, 2]
Output
2
2 appears 3 times out of 5, which is > 5/2.