How hard is LeetCode 1216. Valid Palindrome III?

LeetCode 1216. Valid Palindrome III is rated Hard on LeetCode.

What is the time complexity of LeetCode 1216. Valid Palindrome III?

The Python solution on this page runs in O(n^2).

What is the space complexity of LeetCode 1216. Valid Palindrome III?

The Python solution on this page uses O(n^2) auxiliary space.

What topics does LeetCode 1216. Valid Palindrome III cover?

LeetCode 1216. Valid Palindrome III is tagged String and Dynamic Programming on LeetCode.

Is LeetCode 1216. Valid Palindrome III a premium problem?

Yes. LeetCode 1216. Valid Palindrome III is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.

Valid Palindrome III — LeetCode 1216 Python Solution

HardLeetCode PremiumStringDynamic Programming

Problem: #1216
Pattern: Dynamic Programming
Reading time: 3 min
Source: leetcode.com

The 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

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

Python solution

Python

class Solution:
    def isValidPalindrome(self, s: str, k: int) -> bool:
        n = len(s)
        f = [[0] * n for _ in range(n)]
        for i in range(n):
            f[i][i] = 1
        for i in range(n - 2, -1, -1):
            for j in range(i + 1, n):
                if s[i] == s[j]:
                    f[i][j] = f[i + 1][j - 1] + 2
                else:
                    f[i][j] = max(f[i + 1][j], f[i][j - 1])
                if f[i][j] + k >= n:
                    return True
        return False

Complexity

Measure	Complexity
Time	O(n^2)
Space	O(n^2) auxiliary

Pattern: Dynamic Programming

Define a state, write the transition, and stop recomputing the same subproblem. LeetCode 1216. Valid Palindrome III is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Dynamic Programming.

The dynamic programming guide has the Python template for the pattern and the 481 LeetCode problems that use it.

Frequently asked questions

How hard is LeetCode 1216. Valid Palindrome III?: LeetCode 1216. Valid Palindrome III is rated Hard on LeetCode.
What is the time complexity of LeetCode 1216. Valid Palindrome III?: The Python solution on this page runs in O(n^2).
What is the space complexity of LeetCode 1216. Valid Palindrome III?: The Python solution on this page uses O(n^2) auxiliary space.
What topics does LeetCode 1216. Valid Palindrome III cover?: LeetCode 1216. Valid Palindrome III is tagged String and Dynamic Programming on LeetCode.
Is LeetCode 1216. Valid Palindrome III a premium problem?: Yes. LeetCode 1216. Valid Palindrome III is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.