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.We generate a set of characters to be able to query the existing characters in O(1) time.
We then generate a sliding window that we widen every time we see a new unique character.
When we see a non-unique character, we shorten the sequence until we see the same character, and then continue from there.
class Solution:
def lengthOfLongestSubstring(self, s: str) -> int:
max_so_far, l, r = 0, 0, 0
character_set = set()
str_len = len(s)
while r < str_len:
right_char = s[r]
if right_char in character_set:
while l <= r:
left_char = s[l]
character_set.remove(left_char)
l += 1
if left_char == right_char:
break
character_set.add(right_char)
r += 1
max_so_far = max(max_so_far, r - l)
return max_so_far