Swift - Problem Caesar Chiper Hacker rank challenge

Swift/CaesarCipher.playground/Contents.swift

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+// Problem Caesar Chiper
+// Hacker rank challenge
+// https://www.hackerrank.com/challenges/caesar-cipher-1/problem
+/*
+Julius Caesar protected his confidential information by encrypting it using a cipher. Caesar's cipher shifts each letter by a number of letters. If the shift takes you past the end of the alphabet, just rotate back to the front of the alphabet. In the case of a rotation by 3, w, x, y and z would map to z, a, b and c.
+
+ Original alphabet:      abcdefghijklmnopqrstuvwxyz
+ Alphabet rotated +3:    defghijklmnopqrstuvwxyzabc
+
+ For example, the given cleartext s=There's-a-starman-waiting-in-the-sky and the alphabet is rotated by k=3. The encrypted string is Wkhuh'v-d-vwdupdq-zdlwlqj-lq-wkh-vnb.
+
+ Note: The cipher only encrypts letters; symbols, such as -, remain unencrypted.
+
+ Function Description
+
+ Complete the caesarCipher function in the editor below. It should return the encrypted string.
+
+ caesarCipher has the following parameter(s):
+
+ s: a string in cleartext
+ k: an integer, the alphabet rotation factor
+ Input Format
+
+ The first line contains the integer, , the length of the unencrypted string.
+ The second line contains the unencrypted string, .
+ The third line contains , the number of letters to rotate the alphabet by.
+
+ Constraints
+
+ 1 <= n <= 100
+ 0 <= k <= 100
+
+
+  is a valid ASCII string without any spaces.
+
+ Output Format
+
+ For each test case, print the encoded string.
+
+ Sample Input
+
+ 11
+ middle-Outz
+ 2
+ Sample Output
+
+ okffng-Qwvb
+ Explanation
+
+ Original alphabet:      abcdefghijklmnopqrstuvwxyz
+ Alphabet rotated +2:    cdefghijklmnopqrstuvwxyzab
+
+ m -> o
+ i -> k
+ d -> f
+ d -> f
+ l -> n
+ e -> g
+ -    -
+ O -> Q
+ u -> w
+ t -> v
+ z -> b
+
+*/
+
+func encryptInput(input: String, rotation: Int) -> String {
+    var encryptedString = String()
+    for char in input.unicodeScalars {
+        var code = Int(char.value)
+        // is lowercased letter
+        if (97...122).contains(char.value) {
+            code += rotation
+            while code > 122 {
+                // reduce until in char range
+                code -= (122 - 96)
+            }
+        // is uppercased letter
+        } else if (65...90).contains(char.value) {
+            code += rotation
+            while code > 90 {
+                // reduce until in char range
+                code -= (90 - 64)
+            }
+        }
+        encryptedString += String(Character(UnicodeScalar(code)!))
+    }
+    return encryptedString
+}
+
+encryptInput(input: "hola", rotation: 1)
+encryptInput(input: "hello", rotation: 2)
+encryptInput(input: "test", rotation: 3)

Swift/CaesarCipher.playground/contents.xcplayground

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios' buildActiveScheme='true'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>