Longest Palindromic Substring

Difficulty: EASY
Avg. time to solve
20 min
Success Rate

Problem Statement
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You are given a string (STR) of length N. Find the longest palindromic substring. If there is more than one palindromic substring with the maximum length, return the one with the smaller start index.

A substring is a contiguous segment of a string.
For example : The longest palindromic substring of "ababc" is "aba", since "aba" is a palindrome and it is the longest substring of length 3 which is a palindrome, there is another palindromic substring of length 3 is "bab" since "aba" starting index is less than "bab", so "aba" is the answer.
Input Format:
The first line of input contains a single integer T, representing the number of test cases or queries to be run. 
Then the T test cases follow.

The first and only one of each test case contains a string (STR).
Output Format :
For every test case, print the longest palindromic substring. 

If there are multiple possible answers then you need to print the substring which has the lowest starting index.
Note :
Do not print anything. It has already been taken care of.

Try to solve it using O(1) space complexity.
Constraints :
1 <= T <= 10
0 <= N <= 10^3

Time Limit: 1 sec
Sample Input 1:
Sample Output 1:
Explanation for input 1:
For string "abccbc" there are multiple palindromic substrings like a,b,c,cc,bccb,cbc. But bccb is of longest length. Thus, answer is bccb.
Sample Input 2:
Sample Output 2:
Explanation for input 2:
For string "aeiou" there are multiple palindromic substrings like a,e,i,o,u, and all of the same length. But "a" palindromic substring has the minimum starting index. Thus, answer is "a".
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