217. Contains Duplicate

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


class Solution {
    public boolean containsDuplicate(int[] nums) {
        HashSet<Integer> set = new HashSet<>();
        // return true when there is a duplicate, break
        // otherwise , traverse until the end , return false 
        for(int num : nums){
            if(set.contains(num)){
                return true;
            }else{
                set.add(num);
            }
        }
        return false;
        
    }
}