Is Minimum Consecutive Cards to Pick Up easy or hard?

The problem is classified as Medium difficulty. The main challenge is recognizing that the smallest valid subarray occurs between two closest duplicate cards and implementing an efficient hash map or sliding window solution.

How to solve Minimum Consecutive Cards to Pick Up in O(n)?

Iterate through the array while storing the last index of each card value in a hash map. When the same value appears again, compute the window length using currentIndex - previousIndex + 1 and update the minimum result. This single-pass strategy ensures linear time complexity.

Minimum Consecutive Cards to Pick Up Python or Java solution?

Both Python and Java solutions typically use a dictionary or HashMap to store card indices. During iteration, compute the distance between the current index and the previous occurrence. This produces an O(n) time solution with simple implementation in either language.

What is the best approach for Minimum Consecutive Cards to Pick Up?

The hash map approach that tracks the last index of each card is the most efficient and simplest solution. As you iterate through the array, check if the card appeared before and compute the distance between the two indices. This produces the smallest consecutive segment containing duplicates in O(n) time and O(n) space.

What data structure is used in Minimum Consecutive Cards to Pick Up?

The primary data structure is a hash table (dictionary or map). It stores the most recent index of each card value so duplicates can be detected instantly during iteration.

What is the time complexity of Minimum Consecutive Cards to Pick Up?

The optimal solutions run in O(n) time because the array is scanned once. Hash map lookups and updates occur in constant time on average. Space complexity is O(n) in the worst case if all card values are unique and stored in the map.

Is Minimum Consecutive Cards to Pick Up asked at Google or Amazon interviews?

Array and hash map problems with duplicate detection frequently appear in interviews at companies like Amazon, Google, and Meta. While this exact problem may vary, the underlying concept of tracking previous indices with a hash table is a common interview pattern.

Description Hints 2 Solution Video 7:59

2260. Minimum Consecutive Cards to Pick Up

Medium54.2% acceptance1 company

You are given an integer array cards where cards[i] represents the value of the i^th card. A pair of cards are matching if the cards have the same value.

Return the minimum number of consecutive cards you have to pick up to have a pair of matching cards among the picked cards. If it is impossible to have matching cards, return -1.

Example 1:

Input: cards = [3,4,2,3,4,7]
Output: 4
Explanation: We can pick up the cards [3,4,2,3] which contain a matching pair of cards with value 3. Note that picking up the cards [4,2,3,4] is also optimal.

Example 2:

Input: cards = [1,0,5,3]
Output: -1
Explanation: There is no way to pick up a set of consecutive cards that contain a pair of matching cards.

Constraints:

1 <= cards.length <= 10⁵
0 <= cards[i] <= 10⁶

Asked at 1 company

Google

Topics

Hints open one at a time

Hint 1

Iterate through the cards and store the location of the last occurrence of each number.

Hint 2

What data structure could you use to get the last occurrence of a number in O(1) or O(log n)?

7:59

Still stuck?Read 3 approaches, or watch a walkthrough.

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