[Lintcode]46. Majority Element/[Leetcode]169. Majority Element

Posted 2021-02-08 siriusli

46. Majority Element/[169. Majority Element(https://leetcode.com/problems/majority-element/)

• 本题难度: Easy
• Topic: Greedy

Description

Given an array of integers, the majority number is the number that occurs more than half of the size of the array. Find it.

Example
Example1:
Given [1, 1, 1, 1, 2, 2, 2], return 1
Example2:
Given [1, 1, 1, 2, 2, 2, 2], return 2
Challenge
O(n) time and O(1) extra space

Notice
You may assume that the array is non-empty and the majority number always exist in the array.

我的代码

class Solution:
    """
    @param: nums: a list of integers
    @return: find a  majority number
    """
    def majorityNumber(self, nums):
        # write your code here
        nums.sort()
        return nums[len(nums)//2]

思路

超过了1/2，所以最中间的元素肯定是决定最多元素

• 时间复杂度 nlog(n)