Contains Duplicate
EasyArrayHash Table
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
Input:
nums = [1,2,3,1]Output:
trueExplanation:
Using a hash set to track seen values, This finds that 1 appears at index 0 and again at index 3, confirming a duplicate exists.
Input:
nums = [1,2,3,4]Output:
falseExplanation:
After checking all elements against a hash set, no value is encountered twice. Each of 1, 2, 3, and 4 appears exactly once, so no duplicate exists.
Input:
nums = [1,1,1,3,3,4,3,2,4,2]Output:
trueExplanation:
Multiple values repeat: 1 appears twice, 3 appears three times, 4 appears twice, and 2 appears twice. The algorithm returns true as soon as the first duplicate is detected.
Constraints
- •
1 ≤ nums.length ≤ 10⁵ - •
-10⁹ ≤ nums[i] ≤ 10⁹