 6/19/2017 - 10:20 AM

## 3. Longest Substring Without Repeating Characters

1. Longest Substring Without Repeating Characters
``````class Solution(object):
def lengthOfLongestSubstring(self, s):
"""
:type s: str
:rtype: int
"""
recd = [-1] * 256
start = 0; max_len = 0
for end in range(len(s)):
if recd[ord(s[end])] >= start:
start = recd[ord(s[end])] + 1
recd[ord(s[end])] = end
max_len = max(end - start + 1, max_len)
return max_len``````
``````class Solution(object):
def lengthOfLongestSubstring(self, s):
"""
:type s: str
:rtype: int
"""
recd = [False] * 256
start = 0; max_len = 0
for end in range(len(s)):
if recd[ord(s[end])] == True:
while s[start] != s[end]:
recd[ord(s[start])] = False
start += 1
start += 1
recd[ord(s[end])] = True
max_len = max(end - start + 1, max_len)
return max_len``````

https://leetcode.com/problems/longest-substring-without-repeating-characters/#/description

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.