Description
Given a string s, return the length of the longest substring between two equal characters, excluding the two characters. If there is no such substring return -1.
A substring is a contiguous sequence of characters within a string.
Example 1:
Input: s = "aa"
Output: 0
Explanation: The optimal substring here is an empty substring between the two 'a's.
Example 2:
Input: s = "abca" Output: 2 Explanation: The optimal substring here is "bc".
Example 3:
Input: s = "cbzxy" Output: -1 Explanation: There are no characters that appear twice in s.
Constraints:
1 <= s.length <= 300scontains only lowercase English letters.
Solution
Python3
class Solution:
def maxLengthBetweenEqualCharacters(self, s: str) -> int:
res = -1
prev = {}
for i, x in enumerate(s):
if x in prev:
res = max(res, i - prev[x] - 1)
if x not in prev:
prev[x] = i
return res