202. Contains Duplicate
Easy
Frequency Set
Array
Problem
Given an integer array nums, return true if any value appears at least twice in the array. 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
Hints
?? Think about remembering numbers you have already seen.
?? A Set provides fast membership checks.
?? If a number already exists in the Set, you found a duplicate.
Expected Complexity
Time: O(n)
Space: O(n)
Follow-up
Can you solve it in O(n) expected time?
Practice Notes
Attempts: 0
Time spent: 0min
Hints used: 0
JavaScript
00:00
Loading...
Case 1
Case 2
Case 3
Input
[1,2,3,1]Expected
true