丑数

# -*- coding:utf-8 -*-
class Solution:
    def GetUglyNumber_Solution(self, index):       
        if index == 0:
            return 0

        list_2 = [1]
        list_3 = [1]
        list_5 = [1]

        cur_min = None
        for i in range(index):
            cur_min = min(list_2[0], list_3[0], list_5[0])
            for l in [list_2, list_3, list_5]:
                if l[0] == cur_min:
                    l.pop(0)
            list_2.append(cur_min * 2)
            list_3.append(cur_min * 3)
            list_5.append(cur_min * 5)
        return cur_min