Majority Element

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题目描述

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.

题目出处:https://oj.leetcode.com/problems/majority-element/


解题思路

1 辅助map:map<数组中元素的值,该值出现的次数>

2 操作:每次到map中寻找,如果找到:则将value加1并判断是否退出;如果找不到:则将该元素加入。

自己的源代码

package leetcode;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Map.Entry;public class MajorityElement {public static int majorityElement(int[] num) {Map<Integer, Integer> map = new HashMap<Integer, Integer>();int result = num[0];int numLen = num.length;int objNum = numLen/2 + 1;//跳出条件outer:for(int i = 0; i < numLen; i++){Iterator<Entry<Integer, Integer>> it = map.entrySet().iterator();boolean finding = false;while(it.hasNext()){Entry<Integer, Integer> itEntry = it.next();int itKey = itEntry.getKey();int digit = num[i];if(digit == itKey){//如果找到finding = true;int itValue = itEntry.getValue() + 1;itEntry.setValue(itValue);if(itValue == objNum) {result = itKey;break outer;}}}if(!finding){//如果找不到map.put(num[i], 1);}}        return result;    }public static void main(String[] args) {int[] num = {2, 3, 2, 3, 2, 4};System.out.println(MajorityElement.majorityElement(num));}}


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