- Added Swift solution to the "Leader Element" task.

1 files changed, 85 insertions, 0 deletions

diff --git a/challenge-078/mohammad-anwar/swift/ch-1.swift b/challenge-078/mohammad-anwar/swift/ch-1.swift
new file mode 100755
index 0000000000..31e817c050
--- /dev/null
+++ b/challenge-078/mohammad-anwar/swift/ch-1.swift
@@ -0,0 +1,85 @@
+import Foundation
+
+/*
+
+Perl Weekly Challenge - 078
+
+Task #1: Leader Element
+
+https://perlweeklychallenge.org/blog/perl-weekly-challenge-078
+
+*/
+
+enum ParamError: Error {
+    case missingList
+    case invalidList
+}
+
+do {
+    let paramCount:Int = Int(CommandLine.argc)
+
+    if paramCount <= 1 {
+        throw ParamError.missingList
+    }
+
+    let list:String = CommandLine.arguments[1]
+    if isValidList(list) {
+        let array = list.components(separatedBy: ", ")
+
+        var index:Int = 0;
+        var leaderElements = [Int]();
+        while index < array.count - 1 {
+            let max:Int     = findMax(array, index + 1)
+            let current:Int = Int(array[index])!
+
+            if current > max {
+                leaderElements.append(current)
+            }
+            index += 1
+        }
+        leaderElements.append(Int(array[index])!)
+
+        print(array)
+        print(leaderElements)
+    }
+    else {
+        throw ParamError.invalidList
+    }
+}
+catch ParamError.missingList {
+    print("Missing list.")
+}
+catch ParamError.invalidList {
+    print("Invalid list.")
+}
+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
+    }
+}
+
+func findMax(_ array: [String], _ start:Int) -> Int {
+
+    var window = [Int]()
+    for i in start...array.count-1 {
+        window.append(Int(array[i])!)
+    }
+
+    return window.max()!
+}