66 lines
1.6 KiB
Python
66 lines
1.6 KiB
Python
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# Below is the interface for Iterator, which is already defined for you.
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#
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# class Iterator:
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# def __init__(self, nums):
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# """
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# Initializes an iterator object to the beginning of a list.
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# :type nums: List[int]
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# """
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#
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# def hasNext(self):
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# """
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# Returns true if the iteration has more elements.
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# :rtype: bool
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# """
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#
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# def next(self):
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# """
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# Returns the next element in the iteration.
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# :rtype: int
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# """
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class PeekingIterator:
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peeked = None
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def __init__(self, iterator):
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"""
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Initialize your data structure here.
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:type iterator: Iterator
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"""
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self.it = iterator
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def peek(self):
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"""
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Returns the next element in the iteration without advancing the iterator.
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:rtype: int
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"""
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if self.peeked:
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return self.peeked
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self.peeked = self.it.next()
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return self.peeked
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def next(self):
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"""
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:rtype: int
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"""
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if self.peeked:
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tmp, self.peeked = self.peeked, None
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return tmp
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return self.it.next()
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def hasNext(self):
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"""
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:rtype: bool
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"""
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return self.peeked is not None or self.it.hasNext()
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# Your PeekingIterator object will be instantiated and called as such:
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# iter = PeekingIterator(Iterator(nums))
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# while iter.hasNext():
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# val = iter.peek() # Get the next element but not advance the iterator.
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# iter.next() # Should return the same value as [val].
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