code challenge AH 8

challenge8.swift

"Challenge 8: String is rotated
Difficulty: Tricky

Write a function that accepts two strings, and returns true if one string is rotation of the other, taking letter case into account.

Tip: A string rotation is when you take a string, remove some letters from its end, then append them to the front. For example, "swift" rotated by two characters would be "ftswi".

Sample input and output
The string "abcde" and "eabcd" should return true.
The string "abcde" and "cdeab" should return true.
The string "abcde" and "abced" should return false; this is not a string rotation.
The string "abc" and "a" should return false; this is not a string rotation.
"

Excerpt From: Paul Hudson. "Swift Coding Challenges." Apple Books. 

func checkRotation(string1: String, string2: String) -> Bool {
    guard string1.count == string2.count else {
        return false
    }
    let count = string1.count
    var string = string1
    for i in 1...count {
        string.removeLast()
        string.insert(string1[string1.index(string1.endIndex, offsetBy: (i * -1))], at: string.index(string.startIndex, offsetBy: 0))
        if string == string2 {
            return true
        }
        
    }
    return false
}

checkRotation(string1: "abcde", string2: "eabcd")
checkRotation(string1: "abcde", string2: "cdeab")
checkRotation(string1: "abcde", string2: "abced")