LeetCode 3 Longest Substring Without Repeating Characters

Given a string, find the length of the longest substring without repeating characters.

Examples:

Given "abcabcbb", the answer is "abc", which the length is 3.

Given "bbbbb", the answer is "b", with the length of 1.

Given "pwwkew", 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.

求最长非重复子串

比如 "abcabcbb" => "abc" =>长度为3
比如 "bbbbb" => "b" => 长度为1
比如 "pwwkew" => "wke" =>长度为3