数组中出现次数超过一半的数字

数组中有一个数字出现的次数超过数组长度的一半，请找出这个数字。
例如输入一个长度为9的数组{1,2,3,2,2,2,5,4,2}。由于数字2在数组中出现了5次，超过数组长度的一半，因此输出2。如果不存在则输出0。

class Solution:
    def MoreThanHalf(self, numbers):
        length = len(numbers)
        if numbers == None or length <= 0:
            return 0

        result = numbers[0]
        times = 1
        for i in range(1, length):
            if times == 0:
                result = numbers[i]
                times = 1
            elif numbers[i] == result:
                times += 1
            else:
                times -= 1

        if not self.CheckMoreThanHalf(numbers, length, result):
            result = 0
        return result

    def CheckMoreThanHalf(self, numbers, length, num):
        times = 0
        for i in range(length):
            if numbers[i] == result:
                times += 1
        if times * 2 <= length:
            return False
        return True

package main


import "errors"

func MoreThanHalf(nums []int) (int, error) {
    if len(nums) == 0 {return -1, errors.New("array is empty")}

    count := 1
    value := nums[0]
    for i := 1; i<len(nums); i++ {
        if nums[i] == value {
            count += 1
        } else if count == 0 {
            value = num[i]
            count = 1
        } else {
            count -= 1
        }
    }
    if not CheckMoreThanHalf(nums, value) {return -1, errors.New("num's length lower than half of array")}
}

func CheckMoreThanHalf(nums []int, num int) bool {
    count = 0
    for i := 0; i<len(nums); i++ {
        if num[i] == num {
            count += 1
        }
    }
    if count * 2 <= len(nums) {return false}
    return true
}