Leetcode interview question 17.10 Main elements

More than half of the elements in an array are called major elements . To give you one Integers Array , Find out the main elements . If there is no , return -1 . Please design the time complexity as O(N) 、 The space complexity is O(1) Solutions for .

Example 1：

 Input ：[1,2,5,9,5,9,5,5,5]
 Output ：5

Example 2：

 Input ：[3,2]
 Output ：-1

Example 3：

 Input ：[2,2,1,1,1,2,2]
 Output ：2

Code:

class Solution {
    
public:
    int majorityElement(vector<int>& nums) {
    

        sort(nums.begin(),nums.end());
        if(count(nums.begin(),nums.end(),nums[nums.size()/2])>nums.size()/2)
        return nums[nums.size()/2];
        return -1;
        
    }
};