341. Flatten Nested List Iterator.py

#341. Flatten Nested List Iterator
# """
# This is the interface that allows for creating nested lists.
# You should not implement it, or speculate about its implementation
# """
#class NestedInteger:
#    def isInteger(self) -> bool:
#        """
#        @return True if this NestedInteger holds a single integer, rather than a nested list.
#        """
#
#    def getInteger(self) -> int:
#        """
#        @return the single integer that this NestedInteger holds, if it holds a single integer
#        Return None if this NestedInteger holds a nested list
#        """
#
#    def getList(self) -> [NestedInteger]:
#        """
#        @return the nested list that this NestedInteger holds, if it holds a nested list
#        Return None if this NestedInteger holds a single integer
#        """

class NestedIterator:
    def __init__(self, nestedList: [NestedInteger]):
        def flatenlist(nested_list):
            for i in nested_list:
                if i.isInteger():
                    self._integers.append(i.getInteger())
                else:
                    flatenlist(i.getList())
        self._integers = []
        self._pos = -1
        flatenlist(nestedList)
        
    
    def next(self) -> int:
        self._pos += 1
        return self._integers[self._pos]
        
        
        
    
    def hasNext(self) -> bool:
        return self._pos + 1 < len(self._integers)
      
               

# Your NestedIterator object will be instantiated and called as such:
# i, v = NestedIterator(nestedList), []
# while i.hasNext(): v.append(i.next())