Python Programming

A palindrome is a word (or list) that reads the same backwards. Example palindromes: abcdcba, madam.

Here is a recursive function that returns true if the parameter s is a palindrome and false otherwise:

def ispali(s):

if len(s) == 0 or len(s) == 1:

return True

... part A .... # missing. You need to find it out.

The recursive case (part A) is missing. Which of the following options for part A is correct ?

1. return (s[0] == s[-1]) and ispali(s[1:])

2. return (s[0] == s[-1]) and ispali(s[1:-1])

3. return (s[0] == s[:-1]) and ispali(s[1:])

4. return (s[0] == s[-1]) and ispali(s[1:-2])

5. return (s[0] == s[-1]) or ispali(s[1:-1])