- Added Swift solution to "Left Rotation" task.

2 files changed, 97 insertions, 0 deletions

diff --git a/challenge-078/mohammad-anwar/swift/ch-1.swift b/challenge-078/mohammad-anwar/swift/ch-1.swift
index 31e817c050..31e817c050 100755..100644
--- a/challenge-078/mohammad-anwar/swift/ch-1.swift
+++ b/challenge-078/mohammad-anwar/swift/ch-1.swift
diff --git a/challenge-078/mohammad-anwar/swift/ch-2.swift b/challenge-078/mohammad-anwar/swift/ch-2.swift
new file mode 100644
index 0000000000..29ab3ac62f
--- /dev/null
+++ b/challenge-078/mohammad-anwar/swift/ch-2.swift
@@ -0,0 +1,97 @@
+import Foundation
+
+/*
+
+Perl Weekly Challenge - 078
+
+Task #2: Left Rotation
+
+https://perlweeklychallenge.org/blog/perl-weekly-challenge-078
+
+*/
+
+enum ParamError: Error {
+    case missingSource
+    case invalidSource
+    case missingIndex
+    case invalidIndex
+}
+
+do {
+    let paramCount:Int = Int(CommandLine.argc)
+
+    if paramCount <= 1 {
+        throw ParamError.missingSource
+    }
+    if paramCount <= 2 {
+        throw ParamError.missingIndex
+    }
+
+    let source:String = CommandLine.arguments[1]
+    let index:String  = CommandLine.arguments[2]
+    if isValidList(source) {
+        if isValidList(index) {
+            let sourceArray = source.components(separatedBy: ", ")
+            let indexArray  = index.components(separatedBy: ", ")
+
+            var leftRotation = [[Int]]();
+            for i in 0...indexArray.count-1 {
+                var array      = [Int]();
+                let _index:Int = Int(indexArray[i])!
+
+                for j in _index...sourceArray.count-1 {
+                    array.append(Int(sourceArray[j])!)
+                }
+
+                if _index > 0 {
+                    for k in 0..._index-1 {
+                        array.append(Int(sourceArray[k])!)
+                    }
+                }
+
+                leftRotation.append(array)
+            }
+
+            print(leftRotation)
+        }
+        else {
+            throw ParamError.invalidIndex
+        }
+    }
+    else {
+        throw ParamError.invalidSource
+    }
+}
+catch ParamError.missingSource {
+    print("Missing source.")
+}
+catch ParamError.missingIndex {
+    print("Missing index.")
+}
+catch ParamError.invalidSource {
+    print("Invalid source.")
+}
+catch ParamError.invalidIndex {
+    print("Invalid index.")
+}
+catch let error {
+    print(error)
+}
+
+//
+//
+// Functions
+
+func isValidList(_ list:String) -> Bool {
+
+    let pattern = "^[\\-?\\d\\,?\\s?]+$"
+    let regex   = try! NSRegularExpression(pattern: pattern)
+    let range   = NSRange(location: 0, length: list.utf16.count)
+
+    if regex.firstMatch(in: list, options: [], range: range) != nil {
+        return true
+    }
+    else {
+        return false
+    }
+}