面试题 39. 数组中出现次数超过一半的数字

输入: [1, 2, 3, 2, 2, 2, 5, 4, 2]
输出: 2

class Solution:
    def majorityElement(self, nums: List[int]) -> int:
        cnt = major = 0
        for num in nums:
            if cnt == 0:
                major = num
                cnt += 1
            else:
                cnt += (1 if major == num else -1)
        return major

class Solution {
    public int majorityElement(int[] nums) {
        int major = 0, cnt = 0;
        for (int num : nums) {
            if (cnt == 0) {
                major = num;
                ++cnt;
            } else {
                cnt += (num == major ? 1 : -1);
            }
        }
        return major;
    }
}

/**
 * @param {number[]} nums
 * @return {number}
 */
var majorityElement = function (nums) {
  let cnt = 0;
  let mode = -1;
  for (let num of nums) {
    if (!cnt) {
      mode = num;
      cnt++;
    } else {
      if (mode === num) cnt++;
      else cnt--;
    }
  }
  return mode;
  // return nums.sort((a,b)=>a-b)[~~(nums.length/2)]
};