leetcode----------Majority Element

題目	Majority Element
經過率	33.8%
難度	Easy

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.

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

 

   java代碼：

   

public class Solution {
    public int majorityElement(int[] num) {
        int n = num.length;
        HashMap<Integer,Integer> map = new HashMap<Integer,Integer>();
        for(int elem:num){
            if(map.containsKey(elem)){
                map.put(elem,map.get(elem)+1);
            }else{
                map.put(elem,1);
            }
        }
        for(int item:map.keySet()){
            if(map.get(item)>n/2){
                return item;
            }
        }
        return -1;
    }
}