Peeking Iterator - Leetcode Java | Welkin Lan

Peeking Iterator – Leetcode Java | Welkin Lan

next() and hasNext() peek() operation — it essentially peek() at the element that will be returned by the next call to next(). Here is an example. Assume that the iterator is initialized to the beginning of the list: [1, 2, 3] Now you call next() You call next() the final time and it returns 3, the last element. Calling hasNext() A: // Java Iterator interface reference: // https://docs.oracle.com/javase/8/docs/api/java/util/Iterator.html class PeekingIterator implements Iterator { private Integer next; //cache the next peek private Iterator iter; public PeekingIterator(Iterator iterator) { // initialize any member here. iter = iterator; if (iter.hasNext()) { next = iter.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.

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