2019-08-19 剑指 丑数

12min

    def GetUglyNumber_Solution(self, index):
        if index<1:return None
        res=[1]
        p2,p3,p5=0,0,0
        for i in range(index):
            tmp=min(res[p2]*2,res[p3]*3,res[p5]*5)
            if tmp==res[p2]*2:p2+=1
            if tmp==res[p3]*3:p3+=1
            if tmp==res[p5]*5:p5+=1
            res.append(tmp)
        return res[index-1]