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Tested Python solution for LeetCode 1624 with 18 pytest cases. Generate a practice environment with lcpy.
lcpy gen -n 1624 # by problem number
lcpy gen -s largest_substring_between_two_equal_characters # by problem name
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.
Input: s = "aa"
Output: 0
Explanation: The optimal substring here is an empty substring between the two 'a's.
Input: s = "abca"
Output: 2
Explanation: The optimal substring here is "bc".
Input: s = "cbzxy"
Output: -1
Explanation: There are no characters that appear twice in s.
class Solution:
# Time: O(n)
# Space: O(1)
def max_length_between_equal_characters(self, s: str) -> int:
best = -1
first: dict[str, int] = {}
for i, ch in enumerate(s):
j = first.setdefault(ch, i)
if j != i:
best = max(best, i - j - 1)
return best
| Time | Space |
|---|---|
| O(n) | O(1) |