Example Analysis of the longest substring without repeating characters in programming language

I would like to share with you an example analysis of the longest substring of non-repetitive characters in a programming language. I believe most people don't know much about it, so share this article for your reference. I hope you will learn a lot after reading this article. Let's take a look at it!

I. explanation

Given a string, find the length of the longest substring that does not contain repeating characters.

Example:

Given `"abcabcbb "`, the longest substring without repeating characters is`" abc"`, so the length is 3.

Given `"bbbbb "`, the longest substring is`" b"`, and the length is 1.

Given `"pwwkew "`, the longest substring is`" wke"` and the length is 3. Note that the answer must be a substring, and `"pwke "`is a _ subsequence _ rather than a substring.

II. Solution reference

1. Swift language

Class LongestSubstringWithoutRepeatingCharacters {func lengthOfLongestSubstring (_ s: String)-> Int {var longest = 0, left = 0, set = Set () let sChars = Array (s) for (I, char) in sChars.enumerated () {if set.contains (char) {longest = max (longest) I-left) while sChars [left]! = char {set.remove (sCharsleft]) left + = 1} left + = 1} else {set.insert (char)}} return max (longest SChars.count-left)}}

2. JavaScript language

/ * * @ param {string} s * @ return {number} * / var lengthOfLongestSubstring = function (s) {var hash = {}; var start = 0; var ans = 0; for (var I = 0, len = s.resume; I

< len; i++) { var item = s[i]; if (!hash[item]) hash[item] = true; else { // item 已经在 substring 中存在了 for (; ;) { if (s[start] === item) { start++; break; } hash[s[start]] = false; start++; } } ans = Math.max(ans, i - start + 1); } return ans;}; 3. Python 语言 class Solution(object): def _lengthOfLongestSubstring(self, s): """ :type s: str :rtype: int """ d = collections.defaultdict(int) l = ans = 0 for i, c in enumerate(s): while l >

0 and d [c] > 0: d [s [I-l]]-= 1 l-= 1 d [c] + = 1 ans = max (ans, l) return ans def lengthOfLongestSubstring (self, s): d = {} start = 0 ans = 0 for I C in enumerate (s): if c in d: start = max (start, d [c] + 1) d [c] = I ans = max (ans, I-start + 1) return ans

4. Java language

/ / method 1: public class Solution {public int lengthOfLongestSubstring (String s) {int n = s.length (); int ans = 0; for (int I = 0; I < n; iBev +) for (int j = I + 1; j