1216. Valid Palindrome III

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Problem

Given a string s and an integer k, return true if s is a k-palindrome.

A string is k-palindrome if it can be transformed into a palindrome by removing at most k characters from it.

Example 1:

Input: s = "abcdeca", k = 2
Output: true
Explanation: Remove 'b' and 'e' characters.

Example 2:

Input: s = "abbababa", k = 1
Output: true

Constraints:

• 1 <= s.length <= 1000
• s consists of only lowercase English letters.
• 1 <= k <= s.length

Code

516. Longest Palindromic Subsequence

class Solution {
    public boolean isValidPalindrome(String s, int k) {
        int longest = longestPalindromeSubseq(s);

        return s.length() - longest <= k;
    }

    private int longestPalindromeSubseq(String s) {
        int[][] dp = new int[s.length()][s.length()];

        for (int len = 1; len <= s.length(); len++) {
            for (int i = 0; i + len <= s.length(); i++) {
                int j = i + len - 1;

                if (i == j) {
                    dp[i][j] = 1;
                    continue;
                }

                if (s.charAt(i) == s.charAt(j)) {
                    dp[i][j] = dp[i + 1][j - 1] + 2;
                } else {
                    dp[i][j] = Math.max(dp[i + 1][j], dp[i][j - 1]);
                }
            }
        }

        return dp[0][s.length() - 1];
    }
}