Majority Element

Description:

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.

Code:

解法一

int majorityElement(vector<int>& nums) {
        //方法参见剑指Offer
      int result = nums[0];
      int times = 1;
      
      for (int i = 1; i < nums.size(); i++)
      {
          if (times == 0)
          {
              result = nums[i];
              times = 1;
          }
          else if (result == nums[i])
          {
              times++;
          }
          else 
          {
              times--;
          }
      }
      return result;
    }

解法二：hash表

int majorityElement(vector<int>& nums) {
        //方法参见剑指Offer
        unordered_map<int,int>m;
        int n = nums.size();
        for ( int i = 0; i < n; ++i )
        {
            if ( !m.count(nums[i]) )
                m[nums[i]] = 1;
            else
            {
                ++m[nums[i]];
            }
            if ( m[nums[i]] > n/2 )
                return nums[i];
        }
    }