1624. Largest Substring Between Two Equal Characters

Problem

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 <= 300

• s contains only lowercase English letters.

Solution (Java)

class Solution {
    public int maxLengthBetweenEqualCharacters(String s) {
        int maxLen = -1;
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            int lastIndex = s.lastIndexOf(c);
            if (lastIndex != i) {
                maxLen = Math.max(maxLen, Math.abs(lastIndex - i - 1));
            }
        }
        return maxLen;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).