0217._contains_duplicate.md

217. Contains Duplicate

难度: Easy

刷题内容

原题连接

• https://leetcode.com/problems/contains-duplicate/

内容描述

Given an array of integers, find if the array contains any duplicates.

Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.

Example 1:

Input: [1,2,3,1]
Output: true
Example 2:

Input: [1,2,3,4]
Output: false
Example 3:

Input: [1,1,1,3,3,4,3,2,4,2]
Output: true

解题方案

思路 1 - 时间复杂度: O(NlgN)- 空间复杂度: O(1)******

先 sort

class Solution(object):
    def containsDuplicate(self, nums):
        """
        :type nums: List[int]
        :rtype: bool
        """
        nums.sort()
        for i in range(len(nums)-1):
            if nums[i] == nums[i+1]:
                return True
        return False

思路 2 - 时间复杂度: O(N)- 空间复杂度: O(N)******

利用set更简单

class Solution(object):
    def containsDuplicate(self, nums):
        """
        :type nums: List[int]
        :rtype: bool
        """
        return len(nums) != len(set(nums))