3. Longest Substring Without Repeating Characters
https://leetcode.com/problems/longest-substring-without-repeating-characters/
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Intuition
Record unique character, and its last seen position
Sliding window - Expand till you see unique characters
Shrink when next character is duplicate - shrink window to exclude duplicate character
--- Given a string, find the length of the longest substring without repeating characters.
Example 1:
Input: "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.
Example 2:
Input: "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.
Example 3:
Input: "pwwkew" Output: 3 Explanation: The answer is"wke", with the length of 3. Note that the answer must be a substring,"pwke"is a subsequence and not a substring.
Intuition
Record unique character, and its last seen position
Sliding window - Expand till you see unique characters
Shrink when next character is duplicate - shrink window to exclude duplicate character
