<reponame>Fenghuapiao/PyLeetcode
# """
# This is the interface that allows for creating nested lists.
# You should not implement it, or speculate about its implementation
# """
#class NestedInteger(object):
#    def isInteger(self):
#        """
#        @return True if this NestedInteger holds a single integer, rather than a nested list.
#        :rtype bool
#        """
#
#    def getInteger(self):
#        """
#        @return the single integer that this NestedInteger holds, if it holds a single integer
#        Return None if this NestedInteger holds a nested list
#        :rtype int
#        """
#
#    def getList(self):
#        """
#        @return the nested list that this NestedInteger holds, if it holds a nested list
#        Return None if this NestedInteger holds a single integer
#        :rtype List[NestedInteger]
#        """
from collections import deque
class NestedIterator(object):

    def __init__(self, nestedList):
        """
        Initialize your data structure here.
        :type nestedList: List[NestedInteger]
        """
        self.stack = deque(nestedList[::-1])
        self.value = None
        

    def next(self):
        """
        :rtype: int
        """
        self.hasNext()
        ret = self.value
        self.value = None
        return ret

    def hasNext(self):
        """
        :rtype: bool
        """
        if self.value is not None:
            return True
            
        stack = self.stack
        while stack:
            top = stack.pop()
            if top.isInteger():
                self.value = top.getInteger()
                return True
            else:
                stack.extend(top.getList()[::-1])
        return False

# Your NestedIterator object will be instantiated and called as such:
# i, v = NestedIterator(nestedList), []
# while i.hasNext(): v.append(i.next())
# """
# This is the interface that allows for creating nested lists.
# You should not implement it, or speculate about its implementation
# """
#class NestedInteger(object):
#    def isInteger(self):
#        """
#        @return True if this NestedInteger holds a single integer, rather than a nested list.
#        :rtype bool
#        """
#
#    def getInteger(self):
#        """
#        @return the single integer that this NestedInteger holds, if it holds a single integer
#        Return None if this NestedInteger holds a nested list
#        :rtype int
#        """
#
#    def getList(self):
#        """
#        @return the nested list that this NestedInteger holds, if it holds a nested list
#        Return None if this NestedInteger holds a single integer
#        :rtype List[NestedInteger]
#        """
from collections import deque
class NestedIterator(object):

    def __init__(self, nestedList):
        """
        Initialize your data structure here.
        :type nestedList: List[NestedInteger]
        """
        self.stack = deque(nestedList[::-1])
        self.value = None
        

    def next(self):
        """
        :rtype: int
        """
        self.hasNext()
        ret = self.value
        self.value = None
        return ret

    def hasNext(self):
        """
        :rtype: bool
        """
        if self.value is not None:
            return True
            
        stack = self.stack
        while stack:
            top = stack.pop()
            if top.isInteger():
                self.value = top.getInteger()
                return True
            else:
                stack.extend(top.getList()[::-1])
        return False

# Your NestedIterator object will be instantiated and called as such:
# i, v = NestedIterator(nestedList), []
# while i.hasNext(): v.append(i.next())
# """ # This is the interface that allows for creating nested lists. # You should not implement it, or speculate about its implementation # """ #class NestedInteger(object): #    def isInteger(self): #        """ #        @return True if this NestedInteger holds a single integer, rather than a nested list. #        :rtype bool #        """ # #    def getInteger(self): #        """ #        @return the single integer that this NestedInteger holds, if it holds a single integer #        Return None if this NestedInteger holds a nested list #        :rtype int #        """ # #    def getList(self): #        """ #        @return the nested list that this NestedInteger holds, if it holds a nested list #        Return None if this NestedInteger holds a single integer #        :rtype List[NestedInteger] #        """ Initialize your data structure here.
         :type nestedList: List[NestedInteger] :rtype: int :rtype: bool # Your NestedIterator object will be instantiated and called as such: # i, v = NestedIterator(nestedList), [] # while i.hasNext(): v.append(i.next())