Longest Substring Without Repeating Characters: step-by-step visual explanation

Learn the Longest Substring Without Repeating Characters problem with a step-by-step DSA animation. Follow the Sliding Window (String) solution with synced C#, Python, and Java code.

Sliding Window (String) pattern

The right side grows the window. The left side removes letters whenever the current group breaks the rule.

Difficulty: Medium · Approach: Shrink when a letter repeats

Open Algorithm Atlas to watch the full interactive lesson and follow every execution step.

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