[LeetCode]Two Sum III - Data structure design

public class TwoSum {
    
    private HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();

    // Add the number to an internal data structure.
    public void add(int number) {
        if (map.containsKey(number)) {
            map.put(number, map.get(number) + 1);
        } else {
            map.put(number, 1);
        }
    }

    // Find if there exists any pair of numbers which sum is equal to the value.
    public boolean find(int value) {
        for (int key : map.keySet()) {
            int target = value - key;
            if (map.containsKey(target)) {
                if (target != key) {
                    return true;
                } else {
                    if (map.get(key) > 1) {
                        return true;
                    }
                }
            }
        }
        return false;
    }
}


// Your TwoSum object will be instantiated and called as such:
// TwoSum twoSum = new TwoSum();
// twoSum.add(number);
// twoSum.find(value);