RE 169. Majority Element

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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.

class Solution {public:    int majorityElement(vector<int>& nums) {        int cnt = 0;        int ans = 0;        for(int i = 0; i < nums.size(); ++i)        {                        if(cnt == 0)            {                ans = nums[i];                cnt++;            }            else            {                if(nums[i] == ans)                cnt++;                else                cnt--;            }        }        return ans;   }};

class Solution {public:    int majorityElement(vector<int>& nums) {          int i , len, max=0, count=1;          len = nums.size();          max = len/2;          max=max+1;          if(len==1)          return nums[0];          sort(nums.begin(),nums.end());          for(i=0;i<len;i++)             {  if(nums[i]==nums[i+1])                  count++;                else                   {                       if(count>=max)                        return nums[i];                       count=1;                    }                                           }         return 0;            }};

map 暂时看不懂。。

int majorityElement(vector<int>& nums) {    map<int,int> m;    int ret = -1;    for(int i = 0;i<nums.size();i++)    {        m[nums[i]]++;    }    for(map<int,int>::iterator it = m.begin();it != m.end();it++)    {        if((*it).second*2 >= nums.size())        {             ret = (*it).first;             break;        }    }    return ret;}

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