problems(swift): add “1688. Count of Matches in Tournament”

Signed-off-by: Matej Focko <mfocko@redhat.com>

problems/swift/count-of-matches-in-tournament.swift

@@ -0,0 +1,19 @@
+class Solution {
+    func numberOfMatches(_ n: Int) -> Int {
+        var n = n
+
+        var matches = 0
+        while n > 1 {
+            if n % 2 == 0 {
+                matches += n >> 1;
+            } else {
+                matches += n >> 1;
+                n += 2;
+            }
+
+            n >>= 1;
+        }
+
+        return matches
+    }
+}