LC ：https://leetcode-cn.com/problems/majority-element/
    牛客：https://www.nowcoder.com/practice/e8a1b01a2df14cb2b228b30ee6a92163?tpId=13&&tqId=11181&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking

    方法一：

    1. class Solution {
    2.    public int majorityElement(int[] nums) {
    3.         HashMap<Integer, Integer> map = new HashMap<>();
    4.         for (int i = 0; i < nums.length; ++i) {
    5.             if (map.getOrDefault(nums[i], null) == null) {
    6.                 map.put(nums[i], 1);
    7.             } else {
    8.                 map.put(nums[i], map.get(nums[i]) + 1);
    9.             }
    10.         }
    11.         for (Integer integer : map.keySet()) {
    12.             if (map.get(integer) > nums.length / 2) {
    13.                 return integer;
    14.             }
    15.         }
    16.         return 0;
    17.     }
    19. }
    1. class Solution {
    2. public:
    3.         int majorityElement(vector<int> &nums) {
    4.         int count = 0;
    5.         int major;
    6.         for (int x:nums) {
    7.             if (count == 0) {
    8.                 major = x;
    9.                 count += 1;
    10.                 continue;
    11.             }
    12.             if (x == major) {
    13.                 count++;
    14.             } else {
    15.                 count--;
    16.             }
    17.         }
    18.         return major;
    19.     }
    20. };