Leetcode 1346. Check If N and Its Double Exist

1346. Check If N and Its Double Exist

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HashMap

class Solution {
    public boolean checkIfExist(int[] arr) {
        HashMap<Integer, Integer> hashMap = new HashMap<>();

        for (int a : arr) {
            hashMap.put(a, hashMap.getOrDefault(a, 0) + 1);
        }

        for (int a : arr) {
            if (hashMap.containsKey(a * 2)) {

                if (a == 0 && hashMap.get(a) < 2) {
                    continue;
                }
                return true;
            }
        }
        return false;
    }
}