longest_palindrome

Strings: walking and searching32

Objective

Scan a single command-line string and surface the longest contiguous slice that reads the same in both directions.

Steps

The program expects exactly one argument: the string to inspect.
Find the longest contiguous substring that is identical when read left-to-right and right-to-left.
When several candidates share the maximum length, keep the one whose starting index is the smallest (left-most match wins).
Write the result followed by a newline character.
If no argument is provided, print wrong number of arguments followed by a newline. If the argument is the empty string, print only a newline.

examples

$ ./longest_palindrome "racecar"

racecar

$ ./longest_palindrome "abcdcbxyz"

bcdcb

$ ./longest_palindrome "shipitlevell"

level

$ ./longest_palindrome

wrong number of arguments

Constraints

Expected files

longest_palindrome.c

Allowed functions

write

Tests

Run the tests to grade your code

Build

01No arguments

02Single character is its own palindrome

03Entire input is an odd-length palindrome

04Entire input is an even-length palindrome

05Rejects a non-palindromic prefix before an even palindrome

06Matching endpoints alone do not form a palindrome

07Longest palindrome sits inside the string

08Earliest match wins when lengths tie

09Falls back to the first single character

10Dev-culture string with embedded palindrome

longest_palindrome

Objective

Scan a single command-line string and surface the longest contiguous slice that reads the same in both directions.

Steps

The program expects exactly one argument: the string to inspect.
Find the longest contiguous substring that is identical when read left-to-right and right-to-left.
When several candidates share the maximum length, keep the one whose starting index is the smallest (left-most match wins).
Write the result followed by a newline character.
If no argument is provided, print wrong number of arguments followed by a newline. If the argument is the empty string, print only a newline.

examples

$ ./longest_palindrome "racecar"

racecar

$ ./longest_palindrome "abcdcbxyz"

bcdcb

$ ./longest_palindrome "shipitlevell"

level

$ ./longest_palindrome

wrong number of arguments

Constraints

Expected files

longest_palindrome.c

Allowed functions

write

longest_palindrome

Strings: walking and searching32

Objective

Scan a single command-line string and surface the longest contiguous slice that reads the same in both directions.

Steps

The program expects exactly one argument: the string to inspect.
Find the longest contiguous substring that is identical when read left-to-right and right-to-left.
When several candidates share the maximum length, keep the one whose starting index is the smallest (left-most match wins).
Write the result followed by a newline character.
If no argument is provided, print wrong number of arguments followed by a newline. If the argument is the empty string, print only a newline.

examples

$ ./longest_palindrome "racecar"

racecar

$ ./longest_palindrome "abcdcbxyz"

bcdcb

$ ./longest_palindrome "shipitlevell"

level

$ ./longest_palindrome

wrong number of arguments

Constraints

Expected files

longest_palindrome.c

Allowed functions

write

Tests

Run the tests to grade your code

Build

01No arguments

02Single character is its own palindrome

03Entire input is an odd-length palindrome

04Entire input is an even-length palindrome

05Rejects a non-palindromic prefix before an even palindrome

06Matching endpoints alone do not form a palindrome

07Longest palindrome sits inside the string

08Earliest match wins when lengths tie

09Falls back to the first single character

10Dev-culture string with embedded palindrome