217. Contains Duplicate

URL: LeetCode Problem

Problem Description

Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.

Examples:

• Example 1:

  Input: nums = [1,2,3,1]
  Output: true
  

• Example 2:

  Input: nums = [1,2,3,4]
  Output: false
  

• Example 3:

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

Constraints:

• 1 <= nums.length <= 105
• -109 <= nums[i] <= 109

Python3 Solution1

class Solution(object):
    def containsDuplicate(self, nums):
        set_nums = set(nums)
        return len(set_nums) != len(nums)

Explanation1:

1. Compare the length of original given nums and the shorten length of the nums using set.

Memory: O(n)
Time Complexity: O(n)