Algorithm Notes
Summary: Longest Substring Without Repeating — notes not yet curated.
Time: Estimate via loops/recurrences; common classes: O(1), O(log n), O(n), O(n log n), O(n^2)
Space: Count auxiliary structures and recursion depth.
Tip: See the Big-O Guide for how to derive bounds and compare trade-offs.
Big-O Guide
Source
"""
Longest Substring Without Repeating
Problem: Longest Substring Without Repeating Characters
LeetCode link: https://leetcode.com/problems/longest-substring-without-repeating-characters/
Description: Given a string, find the length of the longest substring without repeating characters.
"""
from src.interview_workbook.leetcode._registry import register_problem
from src.interview_workbook.leetcode._types import Category, Difficulty
class Solution:
def solve(self, *args):
"""Return length of longest substring without repeating characters."""
(s,) = args
seen = {}
l = 0
res = 0
for r, ch in enumerate(s):
if ch in seen and seen[ch] >= l:
l = seen[ch] + 1
seen[ch] = r
res = max(res, r - l + 1)
return res
def demo():
"""TODO: Implement demo function."""
pass
register_problem(
id=3,
slug="longest_substring_without_repeating",
title="Longest Substring Without Repeating Characters",
category=Category.SLIDING_WINDOW,
difficulty=Difficulty.MEDIUM,
tags=["string", "sliding_window", "hashmap"],
url="https://leetcode.com/problems/longest-substring-without-repeating-characters/",
notes="",
)