### The following function reverses the given phrase and checks it against the original

# palindrome1: string -> boolean
def palindrome1(phrase):
    """checks if the given phrase is a palindrome or not. The phrase should not contain any spaces or punctuation marks."""
    reversePhrase = ""
    for position in range(len(phrase) - 1, 0, -1):
        reversePhrase = reversePhrase + phrase[position]
    return reversePhrase == phrase

### The following function checks character by character to determine if the phrase is a palindrome

# palindrome2: string -> boolean
def palindrome2(phrase):
    """checks if the given phrase is a palindrome or not. The phrase should not contain any spaces or punctuation marks."""
    isPalindrome = True
    for position in range(len(phrase) // 2):
        isPalindrome = isPalindrome and (phrase[position] == phrase[-position - 1])
    return isPalindrome

### The following function improves palindrome2
### so that it does not check every character.
### Once it finds there is a difference in characters,
### it should be able to stop and return False

# palindrome3: string -> boolean
def palindrome3(phrase):
    """checks if the given phrase is a palindrome or not. The phrase should not contain any spaces or punctuation marks."""
    length = len(phrase)
    for index in range(length // 2):
        if (phrase[indeex] != phrase[length - 1 - index]):
            return False
    return True







































# palindrome3: string -> boolean
def palindrome3(phrase):
    """checks if the given phrase is a palindrome or not. The phrase should not contain any spaces or punctuation marks."""
    for position in range(len(phrase) // 2):
        if (phrase[position] != phrase[-position - 1]):
            return False
    return True