33-丑数.py

# -*- coding:utf-8 -*-
class Solution:
    def GetUglyNumber_Solution(self, index):
        # write code here
        if not index:
            return 0
        
        ugly_number = [1]*index
        next_index = 1
        
        index2 = 0
        index3 = 0
        index5 = 0
        
        while next_index < index:
            minValue = min(ugly_number[index2]*2, ugly_number[index3]*3,ugly_number[index5]*5)
            ugly_number[next_index] = minValue
            
            while ugly_number[index2]*2 <= ugly_number[next_index]:
                index2 += 1
                
            while ugly_number[index3]*3 <= ugly_number[next_index]:
                index3 += 1
                
            while ugly_number[index5]*5 <= ugly_number[next_index]:
                index5 += 1
                
            next_index += 1
            
        return ugly_number[-1]