How hard is LeetCode 2847. Smallest Number With Given Digit Product?

LeetCode 2847. Smallest Number With Given Digit Product is rated Medium on LeetCode.

What is the time complexity of LeetCode 2847. Smallest Number With Given Digit Product?

The Python solution on this page runs in O(\log n).

What is the space complexity of LeetCode 2847. Smallest Number With Given Digit Product?

The Python solution on this page uses O(1) auxiliary space.

What topics does LeetCode 2847. Smallest Number With Given Digit Product cover?

LeetCode 2847. Smallest Number With Given Digit Product is tagged Greedy and Math on LeetCode.

Is LeetCode 2847. Smallest Number With Given Digit Product a premium problem?

Yes. LeetCode 2847. Smallest Number With Given Digit Product is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.

Smallest Number With Given Digit Product — LeetCode 2847 Python Solution

MediumLeetCode PremiumGreedyMath

Problem: #2847
Pattern: Greedy
Reading time: 2 min
Source: leetcode.com

The problem

Given a positive integer n, return a string representing the smallest positive integer such that the product of its digits is equal to n, or "-1" if no such number exists.

Example

Input: n = 105
Output: "357"
Explanation: 3 * 5 * 7 = 105. It can be shown that 357 is the smallest number with a product of digits equal to 105. So the answer would be "357".

Python solution

Python

class Solution:
    def smallestNumber(self, n: int) -> str:
        cnt = [0] * 10
        for i in range(9, 1, -1):
            while n % i == 0:
                n //= i
                cnt[i] += 1
        if n > 1:
            return "-1"
        ans = "".join(str(i) * cnt[i] for i in range(2, 10))
        return ans if ans else "1"

Complexity

Measure	Complexity
Time	O(\log n)
Space	O(1) auxiliary

Pattern: Greedy

Take the locally best option every time — when you can prove that never costs you later. LeetCode 2847. Smallest Number With Given Digit Product is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Greedy.

The greedy guide has the Python template for the pattern and the 346 LeetCode problems that use it.

Frequently asked questions

How hard is LeetCode 2847. Smallest Number With Given Digit Product?: LeetCode 2847. Smallest Number With Given Digit Product is rated Medium on LeetCode.
What is the time complexity of LeetCode 2847. Smallest Number With Given Digit Product?: The Python solution on this page runs in O(\log n).
What is the space complexity of LeetCode 2847. Smallest Number With Given Digit Product?: The Python solution on this page uses O(1) auxiliary space.
What topics does LeetCode 2847. Smallest Number With Given Digit Product cover?: LeetCode 2847. Smallest Number With Given Digit Product is tagged Greedy and Math on LeetCode.
Is LeetCode 2847. Smallest Number With Given Digit Product a premium problem?: Yes. LeetCode 2847. Smallest Number With Given Digit Product is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.