Majority Element.cpp

/*
Majority Element
================

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?
*/

class Solution
{
public:
  int majorityElement(vector<int> &nums)
  {
    int elem = nums[0];
    int count = 1;

    for (int i = 1; i < nums.size(); ++i)
    {
      if (elem == nums[i])
        count++;
      else
      {
        if (count == 0)
        {
          elem = nums[i];
          count = 1;
        }
        else
          count--;
      }
    }
    return elem;
  }
};