题解 | #丑数#

设置1，2，3，4，5；共5个丑数，下一次的丑数一定是质数因子2，3，5两两相乘的最小值，代码如下：

# -*- coding:utf-8 -*-
class Solution:
    def GetUglyNumber_Solution(self, index):
        uglylist = [1,2,3,4,5]
        if index ==0:
            return 0

#         res[0] = 1
        i2 = 0
        i3 = 0
        i5 = 0
        i=1

        while len(uglylist) <= index+1:
            add = min(uglylist[i2]*2, uglylist[i3]*3, uglylist[i5]*5)
            if add == uglylist[i2]*2:                
                i2 = i2+1
            if add == uglylist[i3]*3:
                i3 = i3+1
            if add == uglylist[i5]*5:
                i5 = i5+1
#             print(uglylist)
            if add > uglylist[-1]:
                uglylist.append(add)

        return uglylist[index-1]
        # write code here