2430-maximum-deletions-on-a-string.adoc

2430. Maximum Deletions on a String

{leetcode}/problems/maximum-deletions-on-a-string/[LeetCode - 2430. Maximum Deletions on a String ^]

You are given a string s consisting of only lowercase English letters. In one operation, you can:

• Delete the entire string s, or

• Delete the first i letters of s if the first i letters of s are equal to the following i letters in s, for any i in the range 1 ⇐ i ⇐ s.length / 2.

For example, if s = "ababc", then in one operation, you could delete the first two letters of s to get "abc", since the first two letters of s and the following two letters of s are both equal to "ab".

Return _the maximum number of operations needed to delete all of _`s`.

Example 1:

Input: s = "abcabcdabc"
Output: 2
Explanation:
- Delete the first 3 letters ("abc") since the next 3 letters are equal. Now, s = "abcdabc".
- Delete all the letters.
We used 2 operations so return 2. It can be proven that 2 is the maximum number of operations needed.
Note that in the second operation we cannot delete "abc" again because the next occurrence of "abc" does not happen in the next 3 letters.

Example 2:

Input: s = "aaabaab"
Output: 4
Explanation:
- Delete the first letter ("a") since the next letter is equal. Now, s = "aabaab".
- Delete the first 3 letters ("aab") since the next 3 letters are equal. Now, s = "aab".
- Delete the first letter ("a") since the next letter is equal. Now, s = "ab".
- Delete all the letters.
We used 4 operations so return 4. It can be proven that 4 is the maximum number of operations needed.

Example 3:

Input: s = "aaaaa"
Output: 5
Explanation: In each operation, we can delete the first letter of s.

Constraints:

• 1 ⇐ s.length ⇐ 4000

• s consists only of lowercase English letters.

思路分析

一刷

link:{sourcedir}/_2430_MaximumDeletionsOnAString.java[role=include]

参考资料