What is the optimal time complexity of solving Palindromic Substrings?

The optimized solution achieves a time complexity of O(n) by using sorting, mathematical shortcuts, or hash table lookups.

What is the auxiliary space complexity for Palindromic Substrings?

The space complexity is O(1) since we only use a minimal/constant amount of extra memory for tracking variables (or auxiliary space if dynamic structures are allocated).

What are the typical edge cases we must handle in Palindromic Substrings?

Key edge cases include empty collections, negative or large bounds causing integer overflow, arrays with only one element, or inputs where target criteria are not met.

How can we optimize the brute force approach for Palindromic Substrings?

Brute force methods often inspect all possible combinations. We optimize this by sorting the input list to enable binary search, or tracking processed items in a set to avoid redundant nested loop lookups.

Back to Practice Dashboard

Top 150 InterviewMedium

Palindromic Substrings

Learn how to solve the 'Palindromic Substrings' problem. This detailed resource details brute force and optimized approaches.

Mode Selected

Problem Statement

Medium

Given a string s, return the number of palindromic substrings in it.

A string is a palindrome when it reads the same backward as forward. A substring is a contiguous sequence of characters within the string.

Write a function countSubstrings(s: str) -> int.

Constraints

•1 <= len(s) <= 1000
•s consists of lowercase English letters

Examples

Example 1

Input

s = "abc"

Output

Explanation

Three palindromic substrings: "a", "b", "c".

Example 2

Input

s = "aaa"

Output

Explanation

Six palindromic substrings: "a", "a", "a", "aa", "aa", "aaa".

Need a Hint?

Define subproblem states, establish the recurrence relation, and use memoization (top-down) or tabulation (bottom-up).

Edge Cases to Watch

Empty list or null input variables
Single item lists/arrays
Extremely large input bounds causing integer or stack overflow

Ready to Solve?

Open the problem in PyRun's browser-based Python editor. Your code runs fully offline — no server required.

Open in Editor