palindrome-partitioning-iii

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1278. Palindrome Partitioning III (Hard)

You are given a string s containing lowercase letters and an integer k. You need to :

• First, change some characters of s to other lowercase English letters.
• Then divide s into k non-empty disjoint substrings such that each substring is palindrome.

Return the minimal number of characters that you need to change to divide the string.

 

Example 1:

Input: s = "abc", k = 2
Output: 1
Explanation: You can split the string into "ab" and "c", and change 1 character in "ab" to make it palindrome.

Example 2:

Input: s = "aabbc", k = 3
Output: 0
Explanation: You can split the string into "aa", "bb" and "c", all of them are palindrome.

Example 3:

Input: s = "leetcode", k = 8
Output: 0

 

Constraints:

• 1 <= k <= s.length <= 100.
• s only contains lowercase English letters.

Related Topics

[Dynamic Programming]

Hints

Hint 1

For each substring calculate the minimum number of steps to make it palindrome and store it in a table.

Hint 2

Create a dp(pos, cnt) which means the minimum number of characters changed for the suffix of s starting on pos splitting the suffix on cnt chunks.