Majority Element

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.

Naive Solution:

public class Solution {
    public int majorityElement(int[] nums) {
        HashMap<Integer,Integer> map = new HashMap<>();
        int ans = 0;
        for(int i = 0; i< nums.length; i++){
            if(!map.containsKey(nums[i])) map.put(nums[i], 1);
            else map.put(nums[i], map.get(nums[i])+1);
            if( map.get(nums[i]) > nums.length/2) ans = nums[i];
        }
        return ans;
    }
}

Genius Solution:

public class Solution {
    public int majorityElement(int[] nums) {
        HashMap<Integer,Integer> map = new HashMap<>();
        int ans = 0;
        for(int i = 0; i< nums.length; i++){
            if(!map.containsKey(nums[i])) map.put(nums[i], 1);
            else map.put(nums[i], map.get(nums[i])+1);
            if( map.get(nums[i]) > nums.length/2) ans = nums[i];
        }
        return ans;
    }
}