[leetcode] Majority Element

Majority Element

class Solution {public:    int majorityElement(vector<int> &num) {        if(num.size()==0){            return -1;        }        int alternative=num[0];        int cnt=1;        for(int i=1;i<num.size();i++){            if(alternative==num[i]){                cnt++;            }else{                cnt--;                if(cnt==0){                    alternative=num[i];                    cnt=1;                }            }        }        //verify the result        cnt=0;        for(int j=0;j<num.size();j++){            if(alternative==num[j]){                cnt++;            }        }        if(cnt>num.size()/2){            return alternative;        }else{            return -1;        }    }};