【LeetCode】169. Majority Element 解题小结

题目：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.

Credits:

自己的思路大概是建立一个map，key对应数字，value对应数字出现的次数，然后比较次数最多的那个应该就是Majority Element。

class Solution {
public:
    unordered_map<int, int> map;
    int majorityElement(vector<int>& nums) {
    int indexMax;
        for (int i = 0; i < nums.size(); i++) {
            if (map.find(nums[i]) == map.end()) {
                map[nums[i]] = 1;
            }
            else {
                map[nums[i]]++;
            }
        }
        indexMax = 0;
        for (int i = 1; i < nums.size(); i++) {
            if (map[nums[i]] > map[nums[indexMax]] && map[nums[i]] >= map.size() / 2)
                indexMax = i;
        }
        return nums[indexMax];
    }
};