Data commit

Task/Knuths-algorithm-S/Java/knuths-algorithm-s-1.java

@@ -0,0 +1,35 @@
+import java.util.*;
+
+class SOfN<T> {
+    private static final Random rand = new Random();
+
+    private List<T> sample;
+    private int i = 0;
+    private int n;
+
+    public SOfN(int _n) {
+        n = _n;
+        sample = new ArrayList<T>(n);
+    }
+
+    public List<T> process(T item) {
+        if (++i <= n) {
+            sample.add(item);
+        } else if (rand.nextInt(i) < n) {
+            sample.set(rand.nextInt(n), item);
+        }
+        return sample;
+    }
+}
+
+public class AlgorithmS {
+    public static void main(String[] args) {
+        int[] bin = new int[10];
+        for (int trial = 0; trial < 100000; trial++) {
+            SOfN<Integer> s_of_n = new SOfN<Integer>(3);
+            for (int i = 0; i < 9; i++) s_of_n.process(i);
+            for (int s : s_of_n.process(9)) bin[s]++;
+        }
+        System.out.println(Arrays.toString(bin));
+    }
+}

Task/Knuths-algorithm-S/Java/knuths-algorithm-s-2.java

@@ -0,0 +1,33 @@
+import java.util.*;
+
+interface Function<S, T> {
+    public T call(S x);
+}
+
+public class AlgorithmS {
+    private static final Random rand = new Random();
+    public static <T> Function<T, List<T>> s_of_n_creator(final int n) {
+        return new Function<T, List<T>>() {
+            private List<T> sample = new ArrayList<T>(n);
+            private int i = 0;
+            public List<T> call(T item) {
+                if (++i <= n) {
+                    sample.add(item);
+                } else if (rand.nextInt(i) < n) {
+                    sample.set(rand.nextInt(n), item);
+                }
+                return sample;
+            }
+        };
+    }
+
+    public static void main(String[] args) {
+        int[] bin = new int[10];
+        for (int trial = 0; trial < 100000; trial++) {
+            Function<Integer, List<Integer>> s_of_n = s_of_n_creator(3);
+            for (int i = 0; i < 9; i++) s_of_n.call(i);
+            for (int s : s_of_n.call(9)) bin[s]++;
+        }
+        System.out.println(Arrays.toString(bin));
+    }
+}