哈希：

class Solution {
public:int majorityElement(vector<int>& nums) {int len=nums.size();unordered_map<int,int> map;for (int i=0;i<len;i++){if(map.find(nums[i])==map.end()){map[nums[i]]=1;}else{map[nums[i]]++;}}int seq=len/2;int ans=nums[0];for(auto pair:map){if(pair.second>seq){ans=pair.first;}}return ans;}
};

随机：

class Solution {
public:int majorityElement(vector<int>& nums) {int len=nums.size();while(true){int index=rand()%len;int res=nums[index];int count=0;for(auto num:nums){if(num==res){++count;}}if(count>len/2){return nums[index];}}return -1;}
};

类似分治：

class Solution {
public:int majorityElement(vector<int>& nums) {int can=-1;int count=0;for(int num:nums){if(count>0){if(num!=can)count--;elsecount++;}else{can=num;count++;}}return can;}};