def nthUglyNumber(self, n):
        """
        :type n: int
        :rtype: int
        """
        ‘‘‘
        #超出时间限制
        
        if n == 0:
            return 0
        i = 1
        while i < n+1:
            m = i
            while m != 1:
                if not m % 2:
                    m = m // 2
                elif not m % 3:
                    m = m //3
                elif not m % 5:
                    m = m // 5
                else:
                    n += 1
                    break
            i +=1
        return n
        ‘‘‘
        #动态规划
        if n<=0:
            return 0
        t1,t2,t3 = 0 , 0 , 0
        res = [1]
        while len(res) < n:
            res.append(min(res[t1]*2,res[t2]*3,res[t3]*5))
            if res[-1] == res[t1] * 2:
                t1 += 1
            if res[-1] == res[t2] * 3:
                t2 += 1
            if res[-1] == res[t3] * 5:
                t3 += 1
        return res[-1]