add chen sort example

Author: hackware1993

example/chen_sort.dart

@@ -0,0 +1,146 @@
+import 'dart:math';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_constraintlayout/flutter_constraintlayout.dart';
+
+import 'custom_app_bar.dart';
+
+class ChenSortExample extends StatefulWidget {
+  const ChenSortExample({Key? key}) : super(key: key);
+
+  @override
+  State createState() => ChenSortExampleState();
+}
+
+class ChenSortExampleState extends State<ChenSortExample> {
+  int defaultNumberCount = 10000;
+  late TextEditingController numberCountController =
+      TextEditingController(text: '$defaultNumberCount');
+  List<String> sortResult = [];
+  bool isSorting = false;
+  ScrollController scrollController = ScrollController();
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: const CustomAppBar(
+        title: 'Chen sort',
+        codePath: 'example/chen_sort.dart',
+      ),
+      body: ConstraintLayout().open(() {
+        const Text(
+          'The time complexity is O(n), the space complexity is O(n), and it is stable',
+          style: TextStyle(
+            fontSize: 30,
+          ),
+        ).applyConstraint(
+          topCenterTo: parent,
+        );
+        TextField(
+          controller: numberCountController,
+          decoration: const InputDecoration(
+            hintText: 'Please enter the number of random numbers',
+          ),
+          inputFormatters: [FilteringTextInputFormatter.digitsOnly],
+        ).applyConstraint(
+          width: 500,
+          outBottomCenterTo: sId(-1).topMargin(20),
+        );
+        ElevatedButton(
+          onPressed: () async {
+            if (isSorting) {
+              setState(() {
+                isSorting = false;
+              });
+            } else {
+              isSorting = true;
+              sortResult.clear();
+              String text = numberCountController.text;
+              if (text.isEmpty) {
+                text = '$defaultNumberCount';
+              }
+              int numberCount = int.parse(text);
+              if (numberCount <= 0) {
+                numberCount = defaultNumberCount;
+              }
+              while (isSorting) {
+                sortResult.add(await compute(compareSort, numberCount));
+                setState(() {
+                  scrollController
+                      .jumpTo(scrollController.position.maxScrollExtent);
+                });
+              }
+            }
+          },
+          child: Text(isSorting ? 'Stop sort' : 'Begin sort'),
+        ).applyConstraint(
+          centerRightTo: sId(-1),
+        );
+        ListView.builder(
+          controller: scrollController,
+          itemBuilder: (_, index) {
+            return Text(sortResult[index]);
+          },
+          itemCount: sortResult.length,
+          itemExtent: 50,
+        ).applyConstraint(
+          width: matchConstraint,
+          height: matchConstraint,
+          outBottomCenterTo: rId(1),
+          bottom: parent.bottom,
+        );
+      }),
+    );
+  }
+}
+
+String compareSort(int numbers) {
+  Random random = Random();
+  var arr = [for (int i = 0; i < numbers; i++) random.nextInt(4294967296)];
+  List copy = List.of(arr);
+  Stopwatch stopwatch = Stopwatch()..start();
+  chenSort(arr);
+  int chenSortTimeUsage = stopwatch.elapsedMicroseconds;
+  stopwatch.reset();
+  copy.sort();
+  int quickSortTimeUsage = stopwatch.elapsedMicroseconds;
+  double percent =
+      ((quickSortTimeUsage - chenSortTimeUsage) / quickSortTimeUsage) * 100;
+  return 'chen sort time usage = $chenSortTimeUsage us, quick sort time usage = $quickSortTimeUsage us, ${percent.toStringAsFixed(2)}% faster';
+}
+
+void chenSort(List<int> list) {
+  int max = -2 ^ 63;
+  for (final element in list) {
+    if (element > max) {
+      max = element;
+    }
+  }
+  int slot;
+  List<List<int>?> buckets = List.filled(list.length + 1, null);
+  double factor = list.length / max;
+  for (final element in list) {
+    slot = (element * factor).toInt();
+    if (buckets[slot] == null) {
+      buckets[slot] = [];
+    }
+    buckets[slot]!.add(element);
+  }
+  int compare(int left, int right) {
+    return left - right;
+  }
+
+  int index = 0;
+  for (final bucket in buckets) {
+    if (bucket != null) {
+      if (bucket.length > 1) {
+        bucket.sort(compare);
+      }
+      for (final element in bucket) {
+        list[index++] = element;
+      }
+    }
+  }
+}

example/home.dart

@@ -5,6 +5,7 @@ import 'arbitrary_position.dart';
 import 'badge.dart';
 import 'barrier.dart';
 import 'charts.dart';
+import 'chen_sort.dart';
 import 'circle_position.dart';
 import 'coming_soon.dart';
 import 'complex_list.dart';
@@ -29,6 +30,8 @@ class ExampleHome extends StatelessWidget {
   ExampleHome({Key? key}) : super(key: key);
 
   final Map<String, Widget?> exampleMap = {
+    'Chen sort(The fastest sorting algorithm in the world, 60% faster than Quicksort)':
+        const ChenSortExample(),
     'Summary': const SummaryExample(),
     'Open Grammar': const OpenGrammarExample(),
     'Guideline': const GuidelineExample(),

example/top_sort.dart

@@ -43,4 +43,5 @@ flutter:
     - example/arbitrary_position.dart
     - example/constraint_controller.dart
     - example/translate.dart
-    - example/open_grammar.dart
+    - example/open_grammar.dart
+    - example/chen_sort.dart