lec_12.cpp

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

// alternative solution
class Solution {
    public:
        int majorityElement(vector<int>& nums) {
    
            int n = nums.size();
    
            map<int , int>mpp;
    
            for(int i = 0 ;i<n;i++){
                mpp[nums[i]]++;
            }
    
            for(auto it:mpp){
                if(it.second > (n/2)){
                    return it.first;
                }
            }
            return -1;
        }
    };

// alternative solution
class Solution {
    public:
        int majorityElement(vector<int>& nums) {
    
            int n = nums.size();
    
            int cnt = 0 ;
            int el ;
    
            for(int i = 0 ;i<n;i++){
                if(cnt == 0){
                    el = nums[i];
                }
                else if(el == nums[i]) cnt++;
                else cnt --;
            }
    
            int cnt1 = 0 ;
            for(int i = 0 ;i<n;i++){
                if(nums[i] == el) cnt1++;
            }
            if(cnt1 >(n/2) ) return el;
            return -1;
        }
    };