10.11 Exercises

Basic Difficulty

566. Reshape the Matrix

This problem is not particularly challenging; it only requires some patience.

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225. Implement Stack using Queues

Using a similar approach, we can also implement a stack using queues.

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503. Next Greater Element II

A variant of the Daily Temperatures problem.

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217. Contains Duplicate

Which data structure would allow us to quickly check for duplicates?

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697. Degree of an Array

How can we preprocess an array to correctly and efficiently compute the length of a subarray?

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594. Longest Harmonious Subsequence

A variant of the Longest Consecutive Sequence problem.

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15. 3Sum

Since the complexity of sorting is $O(n \log n) < O(n^2)$, we can either sort the array first and then perform an $O(n^2)$ pointer search, or directly use a hash table for an $O(n^2)$ search.

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Advanced Difficulty

287. Find the Duplicate Number

A variant of the Find Missing Number problem. Besides marking negative values, are there any other algorithms to solve this?

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313. Super Ugly Number

Try solving this using a priority queue.

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870. Advantage Shuffle

If we need to compare relative sizes and the same number can appear multiple times, which data structure should we use?

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307. Range Sum Query - Mutable

A variant of the Prefix Sum problem. I admit this might be slightly advanced; you might want to look up what a Segment Tree is.