Longest Substring Without Repeating Characters
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. Example 4: Input: s = "" Output: 0 Constraints: 0 <= s.length <= 5 * 10 4 s consists of English letters, digits, symbols and spaces. Approach: Create a HashSet of Characters. Take 2 indexes i (denotes the head of chars) and j (denotes the stretch of chars). public int lengthOfLongestSubstring(String s) { if(s.isEmpty()) return 0; ...