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$ curl repovive.com/roadmaps/fundamental-algorithms/sliding-window/longest-substring-without-repeating

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$ curl repovive.com/roadmaps/fundamental-algorithms/sliding-window/longest-substring-without-repeating

Repovive

Longest Substring Without Repeating - Sliding Window | Fundamental Algorithms | Repovive

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Fundamental Algorithms8 sections · 294 units2h total

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Longest Substring Without Repeating

Classic variable-size window problem.

Problem: Longest substring without repeating characters.

function lengthOfLongestSubstring(s):
    charSet = empty set
    left = 0, maxLen = 0

    for right from 0 to s.length - 1:
        while s[right] in charSet:
            charSet.remove(s[left])
            left++
        charSet.add(s[right])
        maxLen = max(maxLen, right - left + 1)

    return maxLen

Example: "abcabcbb" → max $3$ ("abc").

Time: $O(n)$ . Space: $O(\min(n, alphabet))$ .