01 — Problem Directory

Data Structures & Algorithms

Complete catalog of 99 interactive algorithm visualizers. Browse by data structure category or filter by difficulty.

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All Categories (99)Arrays & Hashing (21)Trees & BST (23)Linked Lists (15)Stack (12)Binary Search (7)Sliding Window (3)Recursion & DP (3)Heap / Priority Queue (1)Backtracking (14)

Easy Medium Hard

Showing 3 of 99 visualizers

Sliding Window

Easy

Contains Duplicate II

Determine if there are two distinct indices i and j such that nums[i] == nums[j] and abs(i - j) <= k using a sliding window hash set.

Sliding WindowHash SetArray

Sliding Window

Medium

Longest Repeating Character Replacement

Find the length of the longest substring containing the same letter you can get after performing at most k character replacements using a dynamic sliding window.

Sliding WindowTwo PointersFrequency Map

Sliding Window

Medium

Minimum Size Subarray Sum

Find the minimal length of a contiguous subarray of which the sum is greater than or equal to target using a dynamic sliding window.

ArrayBinary SearchSliding Window+1