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Leetcode 3. Longest Substring Without Repeating Characters

Find the length of the longest contiguous substring that contains no repeated characters. This is a classic sliding-window / two-pointer problem where you track seen characters to expand and contract the window efficiently (linear-time expected).

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Early October, 2025

Amazon

Mid-level

Mid February, 2025

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Leetcode 3. Longest Substring Without Repeating Characters

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