217. Contains Duplicate - Easy

Posted 2022-06-27 fatttcat

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

 

use hash table (set)

time = O(n), space = O(n)

class Solution 
    public boolean containsDuplicate(int[] nums) 
        Set<Integer> set = new HashSet<>();
        for(int n : nums) 
            if(!set.add(n)) 
                return true;
            
        
        return false;