New update is available. Click here to update.

Solve problems & track your progress

Checkout your overall progress in every topic here

Become

Sensei

in DSA topics

Open the topic and solve more problems associated with it to improve your skills

Check out the skill meter for every topic

See how many problems you are left with to solve for cracking any stage. Score more than zero to get your progress counted.

Problem

Submissions

Longest Palindromic Substring

Contributed by

Ratnesh

Medium

0/80

Avg time to solve 35 mins

Success Rate 78 %

0 upvotes

Problem Statement

You are given a string ‘S’ of length ‘N’.

You must return the longest palindromic substring in ‘S’.

Note: Return any of them in case of multiple substrings with the same length.

Example:

Input: ‘S’ =’badam’

Output: ‘ada’

‘ada’ is the longest palindromic substring, and it can be proved that it is the longest possible palindromic substring.

Detailed explanation ( Input/output format, Notes, Constraints, Images )

Input Format

First-line contains 'T', denoting the number of Test cases.

For each Test case:

The first line contains an integer ‘N’ denoting the string ‘S’ length.
The second line contains the string ‘S’, consisting of lowercase English alphabets.

Output format :

Return the longest palindromic substring in ‘S’.

Note:-

You don't need to print anything. Just implement the given function.

Constraints :

1 <= 'T' <= 10
1 <= 'N' <= 10^5
 ‘a’ <= ‘S[i]’ <= ‘Z’   
Time Limit: 1 sec

Sample Input 1 :

2
6
adccdb
6
aaabbb

Sample Output 1 :

dccd
aaa

Explanation Of Sample Input 1 :

For test case 1:

‘S’ =’adccdb’

‘dccd’ is the longest palindromic substring, and it can be proved that it is the longest possible palindromic substring.
Hence we return ‘dccd’.

For test case 2:

‘S’ =’aaabbb’

‘aaa’ is the longest palindromic substring, and it can be proved that it is the longest possible palindromic substring.
Hence we return ‘dccd’.
‘Bbb’ is also a valid answer.

Sample Input 2 :

2
5
hello
1
a

Sample Output 2 :

ll
a

Auto

Console