Java solution, faster than 99%
\nclass MyHashSet {\n    int[] bitArr;\n    private static final int MAX = 100000;\n    private static final int INT_SIZE = Integer.SIZE;\n\n    public MyHashSe
```\nclass MyHashSet {\n    int[] bitArr;\n    private static final int MAX = 100000;\n    private static final int INT_SIZE = Integer.SIZE;\n\n    public MyHashSet() {\n        bitArr = new int[MAX / INT_SIZE + 1];\n    }\n    \n    public void add(int key) {\n        int ind = key / INT_SIZE;\n        int bit = key % INT_SIZE;\n        int bitMask = 1 << bit;\n        bitArr[ind] |= bitMask;\n    }\n    \n    public void remove(int key) {\n        int ind = key / INT_SIZE;\n        int bit = key % INT_SIZE;\n        int bitMask = ~(1 << bit);\n        bitArr[ind] &= bitMask;\n    }\n    \n    public boolean contains(int key) {\n        int ind = key / INT_SIZE;\n        int bit = key % INT_SIZE;\n        int bitMask = 1 << bit;\n        return (bitArr[ind] & bitMask) != 0;\n    }\n}\n```
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