majority_element.js

/*https://leetcode.com/problems/majority-element/description/

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.*/

var majorityElement = function(nums) {

	var len = nums.length;

	if (len == 1) return nums[0];

	// Empty hash to hold a key-value pair. The key is the majority-element, and the value being the number of times of occurrances of the majority element
	var majorElement = {};

	for ( var i = 0; i < len; i++) {
		var currentElm = nums[i];

		// If the current element already exist in the hash, then increment the count of it. Also check if the count has exceeded [n/2] after incrementing then just reuturn that element, and program execution stops here.
		
		if (majorElement.hasOwnProperty(currentElm)) {
			majorElement[currentElm]++;
			if (majorElement[currentElm] > len/2) return currentElm;
		} else {
			majorElement[currentElm] = 1;  // Create the current element in the hash for the first time
		}
	}
	return "not found";

}

var num = [1,1, 1, 1, 3,4,5];
console.log(majorityElement(num));