class WordDictionary {
    private TreeNode root;
    public static class TreeNode{
        private char data;
        private TreeNode[] child = new TreeNode[26];
        private boolean isEndingChar = false;
        public TreeNode(char data){
            this.data = data;
        }
    }
    /** Initialize your data structure here. */
    public WordDictionary() {
        root = new TreeNode('/');
    }
    
    /** Adds a word into the data structure. */
    public void addWord(String word) {
        TreeNode node = root;
        char[] array = word.toCharArray();
        for(int i = 0 ;i < array.length ; i++){
            int index = array[i] - 'a';
            if(node.child[index] == null){
                node.child[index] = new TreeNode(array[i]);
            }
            node = node.child[index];
        }
        node.isEndingChar = true;
    }
    
    /** Returns if the word is in the data structure. A word could contain the dot character '.' to represent any one letter. */
    public boolean search(String word) {
        if(word == null || word.length() == 0){
            return true;
        }
        TreeNode node = root;
        char[] array = word.toCharArray();
        return helper(array,0,node);       
    }
    public boolean helper(char[] array,int index,TreeNode node){
        if(index == array.length){
            return node.isEndingChar;
        }        
        char data = array[index];
        
        if(data == '.'){ 
            TreeNode[] child = node.child;          
            for(int i = 0 ; i< child.length ; i++){
                
                if(child[i] != null && helper(array, index+1, child[i])){
                    return true;
                }
            }
            return false;
        }else{
            int num = data - 'a';
            if(node.child[num] == null){
                return false;
            }           
            return helper(array,index+1, node.child[num]);
        }
        
    }
}

/**
 * Your WordDictionary object will be instantiated and called as such:
 * WordDictionary obj = new WordDictionary();
 * obj.addWord(word);
 * boolean param_2 = obj.search(word);
 */

/**
 * Linked list node class
 */
static class Node<E> {
    E item;

    /**
     * One of:
     * - the real successor Node
     * - this Node, meaning the successor is head.next
     * - null, meaning there is no successor (this is the last node)
     */
    Node<E> next;

    Node(E x) { item = x; }
}

/** The capacity bound, or Integer.MAX_VALUE if none */
private final int capacity;

/** Current number of elements */
private final AtomicInteger count = new AtomicInteger();

/**
 * Head of linked list.
 * Invariant: head.item == null
 */
transient Node<E> head;

/**
 * Tail of linked list.
 * Invariant: last.next == null
 */
private transient Node<E> last;

/** Lock held by take, poll, etc */
private final ReentrantLock takeLock = new ReentrantLock();
/** Wait queue for waiting takes */
private final Condition notEmpty = takeLock.newCondition();

/** Lock held by put, offer, etc */
private final ReentrantLock putLock = new ReentrantLock();

/** Wait queue for waiting puts */
private final Condition notFull = putLock.newCondition();

/**
 * Creates a {@code LinkedBlockingQueue} with a capacity of
 * {@link Integer#MAX_VALUE}.
 */
public LinkedBlockingQueue() {
    this(Integer.MAX_VALUE);
}

/**
 * Creates a {@code LinkedBlockingQueue} with the given (fixed) capacity.
 *
 * @param capacity the capacity of this queue
 * @throws IllegalArgumentException if {@code capacity} is not greater
 *         than zero
 */
public LinkedBlockingQueue(int capacity) {
    if (capacity <= 0) throw new IllegalArgumentException();
    this.capacity = capacity;
    last = head = new Node<E>(null);
}

/**
 * Inserts the specified element at the tail of this queue, waiting if
 * necessary for space to become available.
 *
 * @throws InterruptedException {@inheritDoc}
 * @throws NullPointerException {@inheritDoc}
 */
public void put(E e) throws InterruptedException {
    if (e == null) throw new NullPointerException();
    // Note: convention in all put/take/etc is to preset local var
    // holding count negative to indicate failure unless set.
    int c = -1;
    Node<E> node = new Node<E>(e);
    final ReentrantLock putLock = this.putLock;
    final AtomicInteger count = this.count;
    putLock.lockInterruptibly();
    try {
        /*
         * Note that count is used in wait guard even though it is
         * not protected by lock. This works because count can
         * only decrease at this point (all other puts are shut
         * out by lock), and we (or some other waiting put) are
         * signalled if it ever changes from capacity. Similarly
         * for all other uses of count in other wait guards.
         */
        while (count.get() == capacity) {
            notFull.await();
        }
        enqueue(node);
        c = count.getAndIncrement();
        if (c + 1 < capacity)
            notFull.signal();
    } finally {
        putLock.unlock();
    }
    if (c == 0)
        signalNotEmpty();
}
/**
 * Links node at end of queue.
 *
 * @param node the node
 */
private void enqueue(Node<E> node) {
    // assert putLock.isHeldByCurrentThread();
    // assert last.next == null;
    last = last.next = node;
}

public E take() throws InterruptedException {
    E x;
    int c = -1;
    final AtomicInteger count = this.count;
    final ReentrantLock takeLock = this.takeLock;
    takeLock.lockInterruptibly();
    try {
        while (count.get() == 0) {
            notEmpty.await();
        }
        x = dequeue();
        c = count.getAndDecrement();
        if (c > 1)
            notEmpty.signal();
    } finally {
        takeLock.unlock();
    }
    if (c == capacity)
        signalNotFull();
    return x;
}
/**
 * Removes a node from head of queue.
 *
 * @return the node
 */
private E dequeue() {
    // assert takeLock.isHeldByCurrentThread();
    // assert head.item == null;
    Node<E> h = head;
    Node<E> first = h.next;
    h.next = h; // help GC
    head = first;
    E x = first.item;
    first.item = null;
    return x;
}

class Trie {
    private TreeNode root;
    public static class TreeNode{
        private char data;
        private TreeNode[] child = new TreeNode[26];
        private boolean isEndingChar = false;
        public TreeNode(char data){
            this.data = data;
        }
    }
    /** Initialize your data structure here. */
    public Trie() {
        root = new TreeNode('/');
    }
    
    /** Inserts a word into the trie. */
    public void insert(String word) {
        TreeNode node = root;
        char[] array = word.toCharArray();
        for(int i = 0 ; i < array.length ; i++){
            int index = array[i] - 'a';
            if(node.child[index] == null){
                node.child[index] = new TreeNode(array[i]);
            }
            node = node.child[index];
        }
        node.isEndingChar = true;
    }
    
    /** Returns if the word is in the trie. */
    public boolean search(String word) {
        TreeNode node = root;
        char[] array = word.toCharArray();
        for(int i = 0 ; i < array.length ; i++){
            int index = array[i] - 'a';
            if(node.child[index] == null){
                return false;
            }
            node = node.child[index];
        }
        if(!node.isEndingChar){
            return false;
        }
        return true;
    }
    
    /** Returns if there is any word in the trie that starts with the given prefix. */
    public boolean startsWith(String prefix) {
        TreeNode node = root;
        char[] array = prefix.toCharArray();
        for(int i = 0 ; i < array.length ; i++){
            int index = array[i] - 'a';
            if(node.child[index] == null){
                return false;
            }
            node = node.child[index];
        }
        return true;
    }
}

/**
 * Your Trie object will be instantiated and called as such:
 * Trie obj = new Trie();
 * obj.insert(word);
 * boolean param_2 = obj.search(word);
 * boolean param_3 = obj.startsWith(prefix);
 */

/**
 * Creates a new {@code DelayQueue} that is initially empty.
 */
public DelayQueue() {}

private final transient ReentrantLock lock = new ReentrantLock();
private final PriorityQueue<E> q = new PriorityQueue<E>();
private Thread leader = null;

/**
 * Condition signalled when a newer element becomes available
 * at the head of the queue or a new thread may need to
 * become leader.
 */
private final Condition available = lock.newCondition();

/**
 * Inserts the specified element into this delay queue.
 *
 * @param e the element to add
 * @return {@code true}
 * @throws NullPointerException if the specified element is null
 */
public boolean offer(E e) {
    final ReentrantLock lock = this.lock;
    lock.lock();
    try {
        q.offer(e);
        if (q.peek() == e) {
            leader = null;
            available.signal();
        }
        return true;
    } finally {
        lock.unlock();
    }
}

/**
 * Retrieves and removes the head of this queue, waiting if necessary
 * until an element with an expired delay is available on this queue.
 *
 * @return the head of this queue
 * @throws InterruptedException {@inheritDoc}
 */
public E take() throws InterruptedException {
    final ReentrantLock lock = this.lock;
    lock.lockInterruptibly();
    try {
        for (;;) {
            E first = q.peek();
            if (first == null)
                available.await();
            else {
                long delay = first.getDelay(NANOSECONDS);
                if (delay <= 0)
                    return q.poll();
                first = null; // don't retain ref while waiting
                if (leader != null)
                    available.await();
                else {
                    Thread thisThread = Thread.currentThread();
                    leader = thisThread;
                    try {
                        available.awaitNanos(delay);
                    } finally {
                        if (leader == thisThread)
                            leader = null;
                    }
                }
            }
        }
    } finally {
        if (leader == null && q.peek() != null)
            available.signal();
        lock.unlock();
    }
}

/**
 * Synchronization control For CountDownLatch.
 * Uses AQS state to represent count.
 */
private static final class Sync extends AbstractQueuedSynchronizer {
    private static final long serialVersionUID = 4982264981922014374L;

    Sync(int count) {
        setState(count);
    }

    int getCount() {
        return getState();
    }

    protected int tryAcquireShared(int acquires) {
        return (getState() == 0) ? 1 : -1;
    }

    protected boolean tryReleaseShared(int releases) {
        // Decrement count; signal when transition to zero
        for (;;) {
            int c = getState();
            if (c == 0)
                return false;
            int nextc = c-1;
            if (compareAndSetState(c, nextc))
                return nextc == 0;
        }
    }
}

public CountDownLatch(int count) {
    if (count < 0) throw new IllegalArgumentException("count < 0");
    this.sync = new Sync(count);
}

public void await() throws InterruptedException {
    sync.acquireSharedInterruptibly(1);
}
public final void acquireSharedInterruptibly(int arg)
        throws InterruptedException {
    if (Thread.interrupted())
        throw new InterruptedException();
    if (tryAcquireShared(arg) < 0)
        doAcquireSharedInterruptibly(arg);
}
private void doAcquireSharedInterruptibly(int arg)
    throws InterruptedException {
    final Node node = addWaiter(Node.SHARED);
    boolean failed = true;
    try {
        for (;;) {
            final Node p = node.predecessor();
            if (p == head) {
                int r = tryAcquireShared(arg);
                if (r >= 0) {
                    setHeadAndPropagate(node, r);
                    p.next = null; // help GC
                    failed = false;
                    return;
                }
            }
            if (shouldParkAfterFailedAcquire(p, node) &&
                parkAndCheckInterrupt())
                throw new InterruptedException();
        }
    } finally {
        if (failed)
            cancelAcquire(node);
    }
}

public void countDown() {
    sync.releaseShared(1);
}
public final boolean releaseShared(int arg) {
    if (tryReleaseShared(arg)) {
        doReleaseShared();
        return true;
    }
    return false;
}