169. Majority Element

169. Majority Element (Easy)

Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times.

You may assume that the array is non-empty and the majority element always exist in the array.

Example 1:

Input: [3,2,3]
Output: 3

Example 2:

Input: [2,2,1,1,1,2,2]
Output: 2

Companies:
Amazon, Google, Microsoft, Facebook

Related Topics:
Array, Divide and Conquer, Bit Manipulation

Solution 1.

// OJ: https://leetcode.com/problems/majority-element/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(1)
class Solution {
public:
    int majorityElement(vector<int>& nums) {
        int ans = 0, cnt = 0;
        for (int n : nums) {
            if (ans == n) ++cnt;
            else if (cnt > 0) --cnt;
            else {
                ans = n;
                cnt = 1;
            }
        }
        return ans;
    }
};