Initial data commit

Task/Knuths-algorithm-S/Objective-C/knuths-algorithm-s.m

@@ -0,0 +1,34 @@
+#import <Foundation/Foundation.h>
+
+typedef NSArray *(^SOfN)(id);
+
+SOfN s_of_n_creator(int n) {
+  NSMutableArray *sample = [[NSMutableArray alloc] initWithCapacity:n];
+  __block int i = 0;
+  return [^(id item) {
+    i++;
+    if (i <= n) {
+      [sample addObject:item];
+    } else if (rand() % i < n) {
+      sample[rand() % n] = item;
+    }
+    return sample;
+  } copy];
+}
+
+int main(int argc, const char *argv[]) {
+  @autoreleasepool {
+
+    NSCountedSet *bin = [[NSCountedSet alloc] init];
+    for (int trial = 0; trial < 100000; trial++) {
+      SOfN s_of_n = s_of_n_creator(3);
+      NSArray *sample;
+      for (int i = 0; i < 10; i++)
+        sample = s_of_n(@(i));
+      [bin addObjectsFromArray:sample];
+    }
+    NSLog(@"%@", bin);
+
+  }
+  return 0;
+}