217. Contains Duplicate java

https://leetcode.com/problems/contains-duplicate/?envType=study-plan&id=programming-skills-i 

Contains Duplicate - LeetCode

class Solution {
    public boolean containsDuplicate(int[] nums) {
        HashMap<Integer,Integer> map = new HashMap<Integer,Integer>();
        for (int num: nums){
            if (map.containsKey(num)){
                return true;
            }
            else {
                map.put(num, 1);
            }
        }
        return false;
    }
}