Data commit

Task/Self-describing-numbers/Swift/self-describing-numbers.swift

@@ -0,0 +1,33 @@
+import Foundation
+
+extension BinaryInteger {
+  @inlinable
+  public var isSelfDescribing: Bool {
+    let stringChars = String(self).map({ String($0) })
+    let counts = stringChars.reduce(into: [Int: Int](), {res, char in res[Int(char), default: 0] += 1})
+
+    for (i, n) in stringChars.enumerated() where counts[i, default: 0] != Int(n) {
+      return false
+    }
+
+    return true
+  }
+}
+
+print("Self-describing numbers less than 100,000,000:")
+
+DispatchQueue.concurrentPerform(iterations: 100_000_000) {i in
+  defer {
+    if i == 100_000_000 - 1 {
+      exit(0)
+    }
+  }
+
+  guard i.isSelfDescribing else {
+    return
+  }
+
+  print(i)
+}
+
+dispatchMain()