Python 刷Leetcode题库，顺带学英语单词（40）

Majority Element

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.     [#169]

Examples:
Input: [3,2,3]
Output: 3
Input: [2,2,1,1,1,2,2]
Output: 2

题意：找出数组中出现次数大于数组长度一半的元素  

>>> n=[3,2,3]
>>> [i for i in n if n.count(i)>len(n)//2][0]
3
>>> n=[2,2,1,1,1,2,2]
>>> [i for i in n if n.count(i)>len(n)//2][0]
2

Majority Element II

Given an integer array of size n, find all elements that appear more than [n/3] times.

Note: The algorithm should run in linear time and in O(1) space.

Examples:
Input: [3,2,3]
Output: [3]
Input: [1,1,1,3,3,2,2,2]
Output: [1,2]

题意：找出数组中出现次数大于数组长度三分之一的元素  

>>> n=[3,2,3]
>>> list({i for i in n if n.count(i)>len(n)//3})
[3]
>>> n=[1,1,1,3,3,2,2,2]
>>> list({i for i in n if n.count(i)>len(n)//3})
[1, 2]
>>>