- Added Swift solution to the task "Truncatable Prime" of week 147.

1 files changed, 111 insertions, 0 deletions

diff --git a/challenge-147/mohammad-anwar/swift/ch-1.swift b/challenge-147/mohammad-anwar/swift/ch-1.swift
new file mode 100644
index 0000000000..933c5cfd56
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+++ b/challenge-147/mohammad-anwar/swift/ch-1.swift
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+import Foundation
+
+/*
+
+Week 147:
+
+    https://theweeklychallenge.org/blog/perl-weekly-challenge-147
+
+Task #1: Truncatable Prime
+
+    Write a script to generate first 20 left-truncatable prime numbers in base 10.
+
+*/
+
+enum ParamError: Error {
+    case missingCount
+    case invalidCount
+}
+
+do {
+    let paramCount:Int = Int(CommandLine.argc)
+
+    if paramCount <= 1 {
+        throw ParamError.missingCount
+    }
+
+    let count:Int = Int(CommandLine.arguments[1])!
+    if count > 0 {
+        var c:Int = 0
+        var n:Int = 2
+        while c < count {
+            if !containZero(String(n)) && isPrime(n) {
+                let numbers:[Int] = leftTruncatableNumbers(n)
+                var found:Bool    = true
+                if numbers.count >= 2 {
+                    for _n in numbers {
+                        if !isPrime(_n) {
+                            found = false
+                        }
+                    }
+                }
+
+                if found {
+                    print(n)
+                    c += 1
+                }
+            }
+
+            n += 1
+        }
+    }
+    else {
+        throw ParamError.invalidCount
+    }
+}
+catch ParamError.missingCount {
+    print("Missing index count.")
+}
+catch ParamError.invalidCount {
+    print("Invalid index count.")
+}
+catch let error {
+    print(error)
+}
+
+//
+//
+// Functions
+
+func containZero(_ n:String) -> Bool {
+
+    let pattern = "0"
+    let regex   = try! NSRegularExpression(pattern: pattern)
+    let range   = NSRange(location: 0, length: n.utf16.count)
+
+    if regex.firstMatch(in: n, options: [], range: range) != nil {
+        return true
+    }
+    else {
+        return false
+    }
+}
+
+func leftTruncatableNumbers(_ n:Int) -> Array<Int> {
+    var numbers  = [Int]()
+    var i:Int    = 0
+    let s:String = String(n)
+    let l:Int    = s.count - 1
+    while i < s.count {
+        numbers.append(Int(String(Array(s)[i...l]))!)
+        i += 1
+    }
+
+    return numbers;
+}
+
+func isPrime(_ n:Int) -> Bool {
+    if n == 1 {
+        return false
+    }
+
+    let j:Int = Int(sqrt(Float(n)))
+    if j >= 2 {
+        for i in 2...j {
+            if n % i == 0 {
+                return false
+            }
+        }
+    }
+    return true
+}