丑数

# -*- coding:utf-8 -*-
class Solution:
    def GetUglyNumber_Solution(self, index):
        # write code here
        if index < 1:
            return 0
        uglylist = [1]
        count = 1
        twopointer = 0
        threepinter = 0
        fivepointer = 0
        while count != index:
            minValue = min(2 * uglylist[twopointer], 3 * uglylist[threepinter], 5 * uglylist[fivepointer])
            uglylist.append(minValue)
            count += 1
            if minValue == 2 * uglylist[twopointer]:
                twopointer += 1
            if minValue == 3 * uglylist[threepinter]:
                threepinter += 1
            if minValue == 5 * uglylist[fivepointer]:
                fivepointer += 1

        return uglylist[count - 1]