Java实现-主元素1

给定一个整型数组，找出主元素，它在数组中的出现次数严格大于数组元素个数的二分之一。

 注意事项

You may assume that the array is non-empty and the majority number always exist in the array.

您在真实的面试中是否遇到过这个题？ 

Yes

样例

给出数组[1,1,1,1,2,2,2]，返回 1

public class Solution {    /**     * @param nums: a list of integers     * @return: find a  majority number     */    public int majorityNumber(ArrayList<Integer> nums) {        // write your code        HashMap<Integer,Integer> map=new HashMap<Integer, Integer>();map.put(nums.get(0), 1);for(int i=1;i<nums.size();i++){if(map.containsKey(nums.get(i))){map.put(nums.get(i), map.get(nums.get(i))+1);}else{map.put(nums.get(i), 1);}}Set<Integer> set=map.keySet();Iterator<Integer> it=set.iterator();while(it.hasNext()){int temp=it.next();if(map.get(temp)>nums.size()/2){return temp;}}return 0;    }}