2414. Length of the Longest Alphabetical Continuous Substring

https://leetcode.com/problems/length-of-the-longest-alphabetical-continuous-substring/description/

An alphabetical continuous string is a string consisting of consecutive letters in the alphabet. In other words, it is any substring of the string "abcdefghijklmnopqrstuvwxyz".

• For example, "abc" is an alphabetical continuous string, while "acb" and "za" are not.

Given a string s consisting of lowercase letters only, return the length of the longest alphabetical continuous substring.

 

Example 1:

Input: s = "abacaba"
Output: 2
Explanation: There are 4 distinct continuous substrings: "a", "b", "c" and "ab".
"ab" is the longest continuous substring.

Example 2:

Input: s = "abcde"
Output: 5
Explanation: "abcde" is the longest continuous substring.

 

Constraints:

• 1 <= s.length <= 105
• s consists of only English lowercase letters.

----

Intuition

Two pointers

if (lo == hi || charAt(hi) - charAt(lo) == 1)

    hi++;

    ans = max(ans, hi - lo) ---> hi - lo = length after increment

else

    lo = hi --- restart a new substring

---

Time - O(N)

Space - O(1)

---

	class Solution {
	public int longestContinuousSubstring(String s) {
	int hi = 0, lo = 0, ans = 1;
	while (hi < s.length()) {
	if (hi == lo || s.charAt(hi) - s.charAt(hi - 1) == 1) {
	hi++;
	ans = Math.max(ans, hi - lo);
	} else {
	lo = hi;
	}
	}
	return ans;
	}
	}

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