問題描述：

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.

問題求解：

解法一：O(n) time O(1) space

class Solution {
public:
    int majorityElement(vector
 
<int>& nums) {
        int n=nums.size();
        int candidate, nTimes;//陣列中的數和次數
        for(int i=0, nTimes=0;i<n;i++)
        {
            if(nTimes==0)
            {
                candidate = nums[i], nTimes=1;
            }
            else
            {
                if(candidate == nums[i])
                {
                    nTimes++;
                }
                else
 

                {
                    nTimes--;
                }
            }
        }
        return candidate;
    }
};

解法二：O(n) time O(1) space

class Solution {
public:
    int majorityElement(vector<int>& nums) {
        int n=nums.size();
        int candidate=nums[0], nTimes=1;//陣列中的數和次數
 

        for(int i=1;i<n;i++)
        {
            if(nums[i] == candidate)
            {
                nTimes++;
            }
            else
            {
                if(nTimes == 0)
                {
                    candidate = nums[i];
                    nTimes = 1;
                }
                else
                {
                    nTimes--;
                }
            }
        }
        return candidate;
    }
};