Majority Element II

Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times. The algorithm should run in linear time and in O(1) space.

方法很笨，其实时间复杂度差不多是O(n²)。

package leetcode;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
//import java.util.Scanner;
import java.util.Set;
public class Solution {
    public List<Integer> majorityElement(int[] nums) {
        List<Integer> result = new ArrayList<Integer>();
        int n = nums.length;
        int m = n/3;
        Set<Integer> myset= new HashSet<Integer>();
        for(int i=0;i<n;i++)
        {
            myset.add(nums[i]);
        }
        Iterator<Integer> iterator = myset.iterator();
        while(iterator.hasNext())
        {
            int thisnum = iterator.next();
            int count = 0;
            for(int i=0;i<n;i++)
            {
                
                if(thisnum == nums[i])
                {
                    count++;
                    if(count>m)
                    {
                        result.add(thisnum);
                        break;
                    }
                }
            }
        }
        return result;
        
    }
    public static void main(String[] args)
    {
        Solution sl = new Solution();
        int[] nums = {2,2,4,6,7,4,2,4};
        List<Integer> result = sl.majorityElement(nums);
        System.out.println(result);
        
    }
}