LeetCode 题解(272) : Zigzag Iterator

题目：

Given two 1d vectors, implement an iterator to return their elements alternately.

For example, given two 1d vectors:

v1 = [1, 2]v2 = [3, 4, 5, 6]

By calling next repeatedly until hasNext returns false, the order of elements returned bynext should be: [1, 3, 2, 4, 5, 6].

Follow up: What if you are given k 1d vectors? How well can your code be extended to such cases?

Clarification for the follow up question - Update (2015-09-18):
The "Zigzag" order is not clearly defined and is ambiguous for k > 2 cases. If "Zigzag" does not look right to you, replace "Zigzag" with "Cyclic". For example, given the following input:

[1,2,3][4,5,6,7][8,9]

It should return [1,4,8,2,5,9,3,6,7].

题解：

Python版：

class ZigzagIterator(object):    def __init__(self, v1, v2):        """        Initialize your data structure here.        :type v1: List[int]        :type v2: List[int]        """        self.l = []        i = 0        while i < max(len(v1), len(v2)):            if i < len(v1):                self.l.append(v1[i])            if i < len(v2):                self.l.append(v2[i])            i += 1        self.index = 0    def next(self):        """        :rtype: int        """        cur = self.l[self.index]        self.index += 1        return cur    def hasNext(self):        """        :rtype: bool        """        if self.index < len(self.l):            return True        else:            return False# Your ZigzagIterator object will be instantiated and called as such:# i, v = ZigzagIterator(v1, v2), []# while i.hasNext(): v.append(i.next())