# #3 Longest Substring Without Repeating Characters LeetCode | Java LeetCode Problem #2023

## 3. 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.
```

Constraints:

• `0 <= s.length <= 5 * 104`
• `s` consists of English letters, digits, symbols and spaces.

## Solution:-

``````class Solution {
public int lengthOfLongestSubstring(String s) {
Set<Character>set=new HashSet<>();
int maxLength=0;
int left=0;
for(int right=0;right<s.length();right++){

if(!set.contains(s.charAt(right))){
maxLength=Math.max(maxLength,right-left+1);

}else{
while(s.charAt(left)!=s.charAt(right)){
set.remove(s.charAt(left));
left++;
}
set.remove(s.charAt(left));left++;