def ladderLength_TLE2(self, start, end, dict):
        def diff_count(str1, str2):
            """
            s1 s2 are same length
            :param s1:
            :param s2:
            :return: 0 1 or -1
            """
            count = 0
            for i in xrange(len(str1)):
                if count>1:
                    return -1
                if str1[i]!=str2[i]:
                    count += 1
            return count

        path_len = 0

        queue = [start]
        while queue:
            path_len += 1
            length = len(queue)
            for i in xrange(length):  #O(V)
                if queue[i]==end:  # reached
                    return path_len

                remain_set = set(dict)
                for item in dict:  # O(k), add next level
                   if diff_count(item, queue[i])==1:
                        queue.append(item)
                        remain_set.remove(item)
                dict = remain_set

            queue = queue[length:]
        return path_len
Returns a UTC timestamp for a C{datetime.datetime} object.
dataset/ETHPy150Open algorhythms/LeetCode/127 Word Ladder.py/Solution.ladderLength_TLE2--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/PyAMF-0.6.1/pyamf/util/__init__.py/get_timestamp