Majority Element II

標籤：

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，其即時間複雜度差不多是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);            }}

 

Majority Element II