How do you solve Divide Array in Sets of K Consecutive Numbers on LeetCode?

Divide Array in Sets of K Consecutive Numbers (LeetCode #1296) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(n log n) time complexity and O(n) space complexity. Key insight: The array must be divisible by k to form complete sets.

What is the time complexity of Divide Array in Sets of K Consecutive Numbers?

The optimal solution for Divide Array in Sets of K Consecutive Numbers runs in O(n log n) time and uses O(n) space. The time complexity is O(n log n) due to the sorting step, and the space complexity is O(n) because we store the counts of the numbers in a hash map.

What is the brute force solution for Divide Array in Sets of K Consecutive Numbers?

The brute force approach for Divide Array in Sets of K Consecutive Numbers is Brute Force, with O(n²) time complexity and O(1) space complexity. The brute-force approach involves checking every possible combination of k consecutive numbers from the array. This means we will repeatedly search for sets of k numbers until we either find a valid grouping or exhaust all possibilities. The optimal Optimal Solution approach improves this to O(n log n).

What algorithm or data structure is used to solve Divide Array in Sets of K Consecutive Numbers?

Divide Array in Sets of K Consecutive Numbers uses the following concepts: Array, Hash Table, Greedy, Sorting. The recommended patterns to study are: Hash Map, Array.

What are the interview tips for Divide Array in Sets of K Consecutive Numbers?

Always consider edge cases, such as arrays with duplicates or lengths not divisible by k. Explain your thought process clearly while coding, as it helps the interviewer understand your reasoning. Practice writing clean, efficient code, as readability is important in interviews.

What are common mistakes when solving Divide Array in Sets of K Consecutive Numbers?

Forgetting to check if the length of the array is divisible by k. Not handling duplicates correctly when forming sets.

#1296

Divide Array in Sets of K Consecutive Numbers

Medium

ArrayHash TableGreedySortingHash MapArray

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n²)	O(n log n)
Space	O(1)	O(n)

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Intuition

Time O(n log n)Space O(n)

The optimal approach uses a hash map to count occurrences of each number and then iteratively builds sets of k consecutive numbers. This is efficient because we only traverse the array a few times, making it faster than the brute-force method.

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Algorithm

5 steps

1Step 1: Check if the length of the array is divisible by k; if not, return false.
2Step 2: Count the occurrences of each number using a hash map.
3Step 3: Iterate through the sorted keys of the hash map, and for each key, try to form a set of k consecutive numbers.
4Step 4: If a set can be formed, decrement the counts in the hash map accordingly.
5Step 5: If all numbers are used up correctly, return true; otherwise, return false.

solution.py14 lines

1# Full working Python code
2from collections import Counter
3
4def canDivideIntoSets(nums, k):
5    if len(nums) % k != 0:
6        return False
7    count = Counter(nums)
8    for num in sorted(count):
9        while count[num] > 0:
10            for i in range(k):
11                if count[num + i] <= 0:
12                    return False
13                count[num + i] -= 1
14    return True

ℹ

Complexity note: The time complexity is O(n log n) due to the sorting step, and the space complexity is O(n) because we store the counts of the numbers in a hash map.

1The array must be divisible by k to form complete sets.
2Using a hash map allows for efficient counting and checking of consecutive numbers.

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