丑数的第n个序列值

微信图片_20191223160147.jpg

class Solution:
    def GetUglyNumber_Solution(self, index):
        # write code here
        if not index:
            return 0
        if index == 1:
            return 1
        p2, p3, p5 = 0, 0, 0
        ret = [1]
        for _ in range(1, index):
            minValue = min(ret[p2]*2, ret[p3]*3, ret[p5]*5)
            ret.append(minValue)
            if minValue == ret[p2]*2:
                p2 += 1
            if minValue == ret[p3]*3:
                p3 += 1
            if minValue == ret[p5]*5:
                p5 += 1
        return minValue