LeetCode Majority Element

1.题目

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.

2.解决方案

class Solution {public:    int majorityElement(vector<int> &num) {        if(num.size() == 1){            return num[0];        }        map<int, int> myMap;        float majorPercent = num.size() / 2.0;        for(int i = 0; i < num.size(); ++i){            int key = num[i];            if(myMap.find(key) == myMap.end()){                myMap.insert(pair<int,int>(key,1));            }else{                int beforeCount = myMap[key];                ++beforeCount;                myMap[key] = beforeCount;                                if(beforeCount > majorPercent){                    return key;                }            }                    }        return 0;    }};

思路:用map当然是比较直线的解决方案。值作为key，出现的次数作为value。

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