How do you solve Create Maximum Number on LeetCode?

Create Maximum Number (LeetCode #321) can be solved using Brute Force. The optimal approach is Brute Force with O(n²) time complexity and O(1) space complexity. Key insight: The brute force approach involves generating all possible combinations of digits from both arrays that can form a number of length k. This is simple but inefficient as it checks every possible combination.

What is the time complexity of Create Maximum Number?

The optimal solution for Create Maximum Number runs in O(n²) time and uses O(1) space. The time complexity is O(n²) because we generate combinations and compare them, which can be very slow as n increases.

What algorithm or data structure is used to solve Create Maximum Number?

Create Maximum Number uses the following concepts: Array, Two Pointers, Stack, Greedy, Monotonic Stack. The recommended patterns to study are: .

Create Maximum Number — LeetCode #321 (Hard)

Tags: Array, Two Pointers, Stack, Greedy, Monotonic Stack

Related patterns:

Brute Force approach

Time complexity: O(n²). Space complexity: O(1).

The brute force approach involves generating all possible combinations of digits from both arrays that can form a number of length k. This is simple but inefficient as it checks every possible combination.

The time complexity is O(n²) because we generate combinations and compare them, which can be very slow as n increases.

Step 1: Generate all possible combinations of digits from nums1 and nums2 that can form a number of length k.
Step 2: For each combination, check if it maintains the relative order of digits from nums1 and nums2.
Step 3: Compare all valid combinations and keep track of the maximum number found.

For nums1 = [3,4,6,5], nums2 = [9,1,2,5,8,3], k = 5: 1. Generate combinations of size 2 from nums1: [3,4], [3,6], [3,5], [4,6], [4,5], [6,5]. 2. Generate combinations of size 3 from nums2: [9,1,2], [9,2,5], [9,5,8], [9,8,3], [1,2,5], [1,5,8], [2,5,8], [5,8,3]. 3. Merge and compare to find max: max([9,8,6,5,3]).

#321

Create Maximum Number

Hard

Array↗Two Pointers↗Stack↗Greedy↗Monotonic Stack↗

LeetCode ↗

Approaches

💡

Intuition

Time O(n²)Space O(1)

⚙️

Algorithm

3 steps

1Step 1: Generate all possible combinations of digits from nums1 and nums2 that can form a number of length k.
2Step 2: For each combination, check if it maintains the relative order of digits from nums1 and nums2.
3Step 3: Compare all valid combinations and keep track of the maximum number found.

solution.py14 lines

1# Full working Python code
2from itertools import combinations
3
4def maxNumber(nums1, nums2, k):
5    max_num = []
6    for i in range(max(0, k - len(nums2)), min(k, len(nums1)) + 1):
7        comb1 = list(combinations(nums1, i))
8        comb2 = list(combinations(nums2, k - i))
9        for c1 in comb1:
10            for c2 in comb2:
11                merged = list(c1) + list(c2)
12                merged.sort(reverse=True)
13                max_num = max(max_num, merged)
14    return max_num

ℹ

Complexity note: The time complexity is O(n²) because we generate combinations and compare them, which can be very slow as n increases.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.