A class for doing quick sorts.

git-svn-id: https://samskivert.googlecode.com/svn/trunk@580 6335cc39-0255-0410-8fd6-9bcaacd3b74c
2002-02-19 03:37:32 +00:00
parent 64136345e0
commit 3900a7da7f
2 changed files with 431 additions and 0 deletions
@@ -0,0 +1,102 @@
+//
+// $Id: QuickSortTest.java,v 1.1 2002/02/19 03:37:32 mdb Exp $
+
+package com.samskivert.util;
+
+import java.util.Comparator;
+
+import junit.framework.Test;
+import junit.framework.TestCase;
+
+/**
+ * Tests the {@link QuickSort} class.
+ */
+public class QuickSortTest extends TestCase
+{
+    public QuickSortTest ()
+    {
+        super(QuickSortTest.class.getName());
+    }
+
+    public void runTest ()
+    {
+        Integer[] a = new Integer[100];
+
+        Comparator comp = new Comparator() {
+            public int compare (Object x, Object y) {
+                return ((Integer)x).intValue() - ((Integer)y).intValue();
+            }
+        };
+
+        for (int d = 1; d <= 100; d++) {
+            for (int n = 0; n < 100; n++) {
+                a[n] = new Integer(n / d);
+                QuickSort.csort (a, 0, n, comp);
+                for (int i = 0; i <= n; i++) {
+                    assert("Failure for up " + n + "/" + d,
+                           a[i].intValue() == i / d);
+                }
+            }
+        }
+        // System.out.println("up test ok");
+
+        for (int d = 1; d <= 100; d++) {
+            for (int n = 0; n < 100; n++) {
+                for (int i = 0; i <= n; i++) {
+                    a[i] = new Integer((n - i) / d);
+                }
+                QuickSort.csort (a, 0, n, comp);
+                for (int i = 0; i <= n; i++) {
+                    assert("Failure for down " + n + "/" + d,
+                           a[i].intValue() == i / d);
+                }
+            }
+        }
+        // System.out.println("down test ok");
+
+        int tests = 1000;
+        for (int sorts = 0; sorts < tests; sorts++) {
+            int n = rand(100);
+            for (int i = 0; i <= n; i++) {
+                a[i] = new Integer(rand(30000));
+            }
+
+            QuickSort.csort (a, 0, n, comp);
+            for (int i = 0; i < n; i++) {
+                assert("Failure for random " + n,
+                       a[i].intValue() <= a[i+1].intValue());
+            }
+
+            QuickSort.csort (a, 0, n, comp);
+            for (int i = 0; i < n; i++) {
+                assert("Failure for random " + n + " (resort)",
+                       a[i].intValue() <= a[i+1].intValue());
+            }
+
+            a[rand(n+1)] = new Integer(rand(30000));
+            QuickSort.csort (a, 0, n, comp);
+            for (int i = 0; i < n; i++) {
+                assert("Failure for random " + n + " (resort 2)",
+                       a[i].intValue() <= a[i+1].intValue());
+            }
+        }
+        // System.out.println("successfully sorted " + tests +
+        // " random arrays");
+    }
+
+    public static Test suite ()
+    {
+        return new QuickSortTest();
+    }
+
+    public static void main (String[] args)
+    {
+        QuickSortTest test = new QuickSortTest();
+        test.runTest();
+    }
+
+    private static int rand (int n)
+    {
+        return (int)(Math.random() * n);
+    }
+}