530. Frequent Enough Letters
A radio operator receives a message s made of lowercase letters. A stretch of consecutive characters of the message is called readable if every letter that appears in the stretch appears at least k times within that same stretch.
Return the length of the longest readable stretch of s. If no non-empty stretch is readable, return 0. Note that a letter that does not appear in a stretch imposes no condition on it.
Example 1
- Input:
- s = "mmmnnoopppp", k = 3
- Output:
- 4
- Explanation:
Counting letters: m=3, n=2, o=2, p=4. The longest stretch with every letter at least 3 times is pppp (length 4).
Example 2
- Input:
- s = "kkjmmmnn", k = 2
- Output:
- 5
- Explanation:
The stretch mmmnn has m three times and n twice, so every letter appears at least 2 times; its length is 5.
Constraints
1 ≤ s.length ≤ 105
1 ≤ k ≤ 105
s consists of lowercase English letters only
How this problem is judged
- Answers
- Your answer must match exactly. Numbers compare by value, so 2 and 2.0 are equal.
- Time per case
- Python 1,200 msC++ 300 msJava 600 msJavaScript 600 msTypeScript 600 ms
Expected complexity
- Time
- O(26 * n)
- Space
- O(1)