Is Smallest Greater Multiple Made of Two Digits easy or hard?

The problem is rated Medium because the brute-force idea is obvious but inefficient. Recognizing that the candidate numbers can be directly generated using only two digits significantly reduces the search space and leads to the optimal solution.

Smallest Greater Multiple Made of Two Digits Python/Java solution

Implement enumeration that builds numbers from digit1 and digit2 up to a fixed digit length. For each number, verify it is greater than k and divisible by k using num % k. The same logic translates directly to Python, Java, C++, and Go with minimal changes.

How to solve Smallest Greater Multiple Made of Two Digits in O(2^n)?

Construct numbers using the two allowed digits with either recursion, iteration, or bitmask enumeration. For every generated number, skip values less than or equal to k and check num % k == 0. Track the smallest valid result among all candidates.

What is the best approach for Smallest Greater Multiple Made of Two Digits?

Digit enumeration is the most efficient strategy. Generate numbers composed only of digit1 and digit2, then check which ones are greater than k and divisible by k. Because each position has only two choices, the search space grows as 2^n and remains small for practical limits.

Is Smallest Greater Multiple Made of Two Digits asked at Google/Amazon/Meta?

Problems involving constrained number construction and divisibility appear frequently in technical interviews at companies like Google, Amazon, and Meta. While this exact problem may not appear verbatim, the enumeration and math techniques are commonly tested.

What data structure is used in Smallest Greater Multiple Made of Two Digits?

The core technique relies on enumeration rather than complex data structures. Candidates are generated using recursion, loops, or bitmasks, and simple arithmetic operations such as modulo are used for divisibility checks.

What is the time complexity of Smallest Greater Multiple Made of Two Digits?

The enumeration approach runs in O(2^n) time where n is the maximum number of digits generated. Each candidate requires a constant-time divisibility check. Space complexity stays O(1) because only a few numeric variables are stored.

Description Hints 2 Solution Video 28:30

1999. Smallest Greater Multiple Made of Two Digits

Medium47.4% acceptance1 companyPremium elsewhere, free here

Given three integers, k, digit1, and digit2, you want to find the smallest integer that is:

Larger than k,
A multiple of k, and
Comprised of only the digits digit1 and/or digit2.

Return the smallest such integer. If no such integer exists or the integer exceeds the limit of a signed 32-bit integer (2³¹ - 1), return -1.

Example 1:

Input: k = 2, digit1 = 0, digit2 = 2
Output: 20
Explanation:
20 is the first integer larger than 2, a multiple of 2, and comprised of only the digits 0 and/or 2.

Example 2:

Input: k = 3, digit1 = 4, digit2 = 2
Output: 24
Explanation:
24 is the first integer larger than 3, a multiple of 3, and comprised of only the digits 4 and/or 2.

Example 3:

Input: k = 2, digit1 = 0, digit2 = 0
Output: -1
Explanation:
No integer meets the requirements so return -1.

Constraints:

1 <= k <= 1000
0 <= digit1 <= 9
0 <= digit2 <= 9

Asked at 1 company

PayPal

Topics

Enumeration Math

Hints open one at a time

Hint 1

Could you generate all the different numbers comprised of only digit1 and digit2 with the constraints?

Hint 2

Going from least to greatest, check if the number you generated is greater than k and a multiple of k.

28:30

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