Is Largest Integer With Given Digit Sum easy or hard?

Largest Integer With Given Digit Sum is generally considered an Easy problem because the core idea is a straightforward greedy observation. The challenge is recognizing that larger leading digits always produce a larger number overall.

Largest Integer With Given Digit Sum Python/Java solution

Python solutions typically use a list of characters followed by ''.join() for efficiency. Java solutions usually rely on StringBuilder to avoid repeated string copies. Both implementations follow the same greedy logic and run in O(n) time.

How to solve Largest Integer With Given Digit Sum in O(n)?

Use a greedy construction strategy. While the remaining digit sum is at least 9, append the digit 9 to the answer and subtract 9 from the sum. After the loop, append the remaining value if it is greater than 0. The algorithm processes each digit once, giving O(n) complexity.

What is the best approach for Largest Integer With Given Digit Sum?

The greedy approach is the best solution because placing the largest possible digit first always maximizes the final integer. Repeatedly append 9 while reducing the remaining digit sum, then append the leftover digit if needed. This runs in O(n) time with O(n) space.

Is Largest Integer With Given Digit Sum asked at Google/Amazon/Meta?

Greedy digit construction problems commonly appear in coding interviews at large tech companies because they test optimization and numeric reasoning. Variants of this problem have shown up in interview prep sets for Amazon, Google, and Meta-style rounds.

What data structure is used in Largest Integer With Given Digit Sum?

Most solutions use a string builder, character array, or list to efficiently append digits while constructing the answer. No advanced data structure is required because the algorithm depends mainly on greedy selection.

What is the time complexity of Largest Integer With Given Digit Sum?

The optimal greedy solution runs in O(n) time, where n is the number of digits in the constructed integer. Each iteration appends one digit and decreases the remaining sum. Space complexity is also O(n) because the output string must be stored.

4000. Largest Integer With Given Digit Sum - Practice Online

You are given two non-negative integers n and s.

Return the largest integer that has at most n digits and whose sum of digits is s. If no such integer exists, return -1.

Example 1:

Input: n = 2, s = 9

Output: 90

Explanation:

The largest integer with at most 2 digits that has a sum of digits of 9 is 90.

Example 2:

Input: n = 2, s = 19

Output: -1

Explanation:

There is no integer with at most 2 digits that has a sum of digits of 19, so the answer is -1.

Example 3:

Input: n = 5, s = 0

Output: 0

Explanation:

The only non-negative integer whose digits sum to 0 is 0.

Constraints:

1 <= n <= 5
0 <= s <= 100