Question

In python...

All functions must use recursion. Do not use any iteration or slicing.

1. Return the reverse of the given string. Use the index argument to keep track of position, which starts at zero.

reverse_string(chars: str, index: int) -> str

2. Return the highest number in the list of integers. Use the index argument to keep track of position, which starts at zero.

find_max(ints: List[int], index: int) -> int

3. Return True if the given string is a palindrome and False otherwise. A palindrome is a symmetric sequence of characters, reading the same forward and backward. Use the index argument to keep track of position, which starts at zero. Do not call reverse_string.

is_palindrome(chars: str, index: int) -> bool

Answer 1

from typing import *


def reverse_string(chars: str, index: int = 0) -> str:
    if index < len(chars):
        return reverse_string(chars, index + 1) + chars[index]
    return ""


# Testing the function here. ignore/remove the code below if not required
print(reverse_string("hello"))
print(reverse_string("how are you?"))


def find_max(ints: List[int], index: int = 0) -> int:
    if index == len(ints) - 1:
        return ints[index]
    else:
        large = find_max(ints, index + 1)
        if ints[index] > large:
            large = ints[index]
        return large


# Testing the function here. ignore/remove the code below if not required
print(find_max([4, 9, 2]))
print(find_max([14, 9, 2]))
print(find_max([4, 9, 21]))


def is_palindrome(chars: str, index: int = 0) -> bool:
    if index >= len(chars):
        return True
    else:
        return is_palindrome(chars, index + 1) and chars[index] == chars[len(chars) - index - 1]


# Testing the function here. ignore/remove the code below if not required
print(is_palindrome("hello"))
print(is_palindrome("radar"))
print(is_palindrome("mom"))
print(is_palindrome("palindrome"))