Merge pull request ignacio-chiazzo#33 from ignacio-chiazzo/majority_element

Added majority element

Author: ignacio-chiazzo

LeetcodeProblems/Majority_Element.js

@@ -0,0 +1,53 @@
+/*
+Majority Element
+https://leetcode.com/problems/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.
+
+Example 1:
+
+Input: [3,2,3]
+Output: 3
+Example 2:
+
+Input: [2,2,1,1,1,2,2]
+Output: 2
+
+Note: You should have a better solution than O(N)
+*/
+
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var majorityElement = function(nums) {
+  if(nums.length === 0)
+    return -1;
+  
+  var candidate = nums[0];
+  var proves = 1;
+  
+  for(var i = 1; i < nums.length; i++) {
+    if(nums[i] === candidate) 
+      proves++;
+    else {
+      proves--;
+      if(proves === 0)  {
+        candidate = nums[i];
+        proves = 1;
+      }
+    }
+  }
+  
+  return candidate;
+};
+
+var main = function() {
+  console.log(majorityElement([2,2,3]));
+  console.log(majorityElement([2,3,2]));
+  console.log(majorityElement([1,1,1,2,3,45,1,2,4,1,1]));
+}
+
+module.exports.main = main

README.md

@@ -56,7 +56,8 @@ Solutions of algorithm problems using Javascript
 | [Valid Parentheses ](/LeetcodeProblems/Valid_Parentheses.js)                                         | Easy   | https://leetcode.com/problems/valid-parentheses/ |
 | [Backspace String Compare ](/LeetcodeProblems/Backspace_String_Compare.js)                           | Easy   | https://leetcode.com/problems/backspace-string-compare/ |
 | [Binary Gap ](/LeetcodeProblems/Binary_Gap.js)                                                       | Easy   | https://leetcode.com/problems/binary-gap/ |
-| [Best Time to Buy and Sell Stock II ](/LeetcodeProblems/Best_Time_To_Buy_And_Sell_Stock_II.js)       | Easy   | https://leetcode.com/problems/best-time-to-buy-and-sell-stock-ii/ |
+| [Binary Gap ](/LeetcodeProblems/Binary_Gap.js)                                                       | Easy   | https://leetcode.com/problems/binary-gap/ |
+| [Majority Element](/LeetcodeProblems/Majority_Element.js)                                            | Easy   | https://leetcode.com/problems/majority-element/ |
 | [Tic Tac Toe ](/LeetcodeProblems/Tic_Tac_Toe.js)                                                     |        | |
 | [Permutations With Duplicates ](/LeetcodeProblems/Permutations_With_Duplicates.js)                   |        | |
 | [Deletion Distance](/LeetcodeProblems/Deletion_Distance.js)                                          |        | |