Orig Description
Problem C: Palindrome
Problem
Taro has N strings of length L each. He loves palindromes, so he wants to choose some of the N strings, arrange them in any order he likes, and make the longest palindrome possible.
Find the longest palindrome that Taro can make. If there are multiple palindromes of the same length, output the lexicographically smallest one. If it is impossible to make a palindrome no matter how he chooses and arranges strings, output an empty line.
Input
The input is given in the following format:
N L
s1
s2
.
.
.
sN
The first line contains two integers N and L which are the number of strings and the length of the strings, respectively. The following N lines contain the strings that Taro has.
Constraints
The input satisfies the following constraints:
1 ≤ N ≤ 1000
1 ≤ L ≤ 30
si consists of lowercase English letters.
Output
Output the lexicographically smallest longest palindrome that can be made. If it is impossible to make a palindrome, output an empty line.
Sample Input 1
4 2
oi
io
rr
rr
Sample Output 1
iorrrroi
Sample Input 2
5 1
a
b
c
a
c
Sample Output 2
acbca
Sample Input 3
3 3
uki
uku
uke
Sample Output 3
uku
Extracted Specification
An integer N (1 ≤ N ≤ 1000), representing some quantity or size.
An integer L (1 ≤ L ≤ 30), representing some length.
A list of N strings, each of length L, consisting of lowercase English letters.
### Example Input:
```
4 2
oi
io
rr
rr
```
### Function Signature:
Write a function f(N, L, strings) that takes in the input.
```python
def f(N: int, L: int, strings: List[str]):
'''
N: an integer
L: an integer
strings: a list of strings
'''
```
Test Case Generator
Here is a test case generator for the given problem "Palindrome":
```python
import random
import string
def generate_random_string(length):
return ''.join(random.choices(string.ascii_lowercase, k=length))
def tcgen():
# Generate random N and L based on the problem constraints
N = random.randint(1, 1000)
L = random.randint(1, 30)
# Generate N random strings of length L
strings = [generate_random_string(L) for _ in range(N)]
return N, L, strings
# Example usage of the test case generator
N, L, strings = tcgen()
print(N, L)
for s in strings:
print(s)
```
### Explanation:
1. **generate_random_string(length)**: This helper function generates a random string of a given length composed of lowercase English letters.
2. **tcgen()**: The main function that generates a test case:
- It first generates random values for \(N\) (number of strings) and \(L\) (length of each string) within the given constraints.
- It then creates a list of \(N\) random strings, each of length \(L\), using the `generate_random_string` function.
### Example Usage:
Running the provided example will generate a random test case every time:
```plaintext
532 27
lguvkjjepzvazgnmvwalyncdnyy
sxnbbwlzizbfvcmxyvbxcrhmtrh
...
```
Each run will produce different values for \(N\), \(L\), and the list of strings. This makes it a useful tool for generating diverse test cases for the problem.
Extract Arguments
def extract_arguments(fh):
N, L = map(int, fh.readline().strip().split())
strings = [fh.readline().strip() for _ in range(N)]
return N, L, strings
# if __name__ == "__main__":
# input_path = sys.argv[1]
# with open(input_path, 'r') as fh:
# N, L, strings = extract_arguments(fh)
# f(N, L, strings)