LeetCode 169：Majority Element

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.

Example 1:

Input: [3,2,3]
Output: 3
Example 2:

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

C++
   int majorityElement(vector<int>& nums) {
        int length = nums.size();
        int start = 0;
        int end = nums.size() - 1;
        int middle = length>>1;
        int index = Partition(nums,start,end);
        while(index != middle)
        {
            if(index < middle)
            {
                start = index + 1;
                index = Partition(nums,start,end);
            }
            else
            {
                end = index - 1;
                index = Partition(nums,start,end);
            }
        }
        return nums[index];
    }
    int Partition(vector<int>& nums,int left,int right)
    {
        if(nums.size() == 0||left < 0||right < left)
            return 0;
        int i = left;
        int j = right;
        int temp = nums[i];
        while(i != j)
        {
            while(i < j&&nums[j] >= temp)--j;
            nums[i] = nums[j];
            while(i < j&&nums[i] <= temp)++i;
            nums[j] = nums[i];
        }
        nums[i] = temp;
        return i;
    }