Leetcode 229. Majority Element II

public class Solution { public List<Integer> majorityElement(int[] nums) { List<Integer> res = new ArrayList<Integer>(); if (nums.length == 0) return res; int candidate1 = 0, count1 = 0; int candidate2 = 0, count2 = 0; for (int num : nums) { if (candidate1 == num) count1++; else if (candidate2 == num) count2++; else if (count1 == 0) { candidate1 = num; count1 = 1; } else if (count2 == 0) { candidate2 = num; count2 = 1; } else { count1--; count2--; } } // check if cadidates are majority element count1 = 0; count2 = 0; for (int num : nums) { if (num == candidate1) count1++; // use 'else if' other than 'if' to avoid duplicate e.g. input [0, 0, 0] else if (num == candidate2) count2++; } if (count1 > nums.length/3) res.add(candidate1); if (count2 > nums.length/3) res.add(candidate2); return res; } }