LeetCode : 284. Peeking Iterator

// Java Iterator interface reference:
// https://docs.oracle.com/javase/8/docs/api/java/util/Iterator.html
class PeekingIterator implements Iterator<Integer> {
        Iterator<Integer> it;
        Integer next;

        public PeekingIterator(Iterator<Integer> iterator) {
        // initialize any member here.
            it = iterator;
            if (it.hasNext()) next = it.next();
        }

        // Returns the next element in the iteration without advancing the iterator.
    public Integer peek() {
        return next;
    }

    // hasNext() and next() should behave the same as in the Iterator interface.
    // Override them if needed.
    @Override
    public Integer next() {
            Integer temp = next;
            if (it.hasNext()) next = it.next();
            else next = null; // !!!

        return temp;
    }

    @Override
    public boolean hasNext() {
            return next != null;
    }
}
congr / world

LeetCode : 284. Peeking Iterator #463
