Leetcode Longest Substring Without Repeating Characters
Question
Given a string s, find the length of the longest substring without repeating characters. Example 1: Input: s = "abcabcbb" Output: 3 Explanation: The answer is "abc", with the length of 3. Example 2: Input: s = "bbbbb" Output: 1 Explanation: The answer is "b", with the length of 1. Example 3: Input: s = "pwwkew" Output: 3 Explanation: The answer is "wke", with the length of 3. Notice that the answer must be a substring, "pwke" is a subsequence and not a substring. Constraints: 0 <= s.length <= 5 * 104 s consists of English letters, digits, symbols and spaces.
Initial thought process
let us consider a string ABCDAEJKL. So my initial thought process was I started counting with a letter and as soon as I found it has been repeated I used to reset the counter. So my answer for above string would be 5 but it was an obvious mistake as I was skipping the characters after first A, the solution to this was to maintain a map and position of every character and as a character is repeated we take starting point of the next count or next substring from the first appearance (in the current substring) of the repeating character and update the map with repeated postition or new latest location of the repeating character.
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