| // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| /// Tests algorithm utilities. |
| |
| import "package:collection/collection.dart"; |
| import "package:unittest/unittest.dart"; |
| import 'dart:math'; |
| |
| void main() { |
| void testShuffle(List list) { |
| List copy = list.toList(); |
| shuffle(list); |
| expect(new UnorderedIterableEquality().equals(list, copy), isTrue); |
| } |
| |
| test("Shuffle 0", () { |
| testShuffle([]); |
| }); |
| test("Shuffle 1", () { |
| testShuffle([1]); |
| }); |
| test("Shuffle 3", () { |
| testShuffle([1, 2, 3]); |
| }); |
| test("Shuffle 10", () { |
| testShuffle([1, 2, 3, 4, 5, 1, 3, 5, 7, 9]); |
| }); |
| test("Shuffle shuffles", () { |
| List l = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]; |
| List c = l.toList(); |
| int count = 0; |
| do { |
| shuffle(l); |
| if (!const ListEquality().equals(c, l)) return; |
| // Odds of not changing the order should be one in ~ 16! ~= 2e+13. |
| // Repeat this 10 times, and the odds of accidentally shuffling to the |
| // same result every time is disappearingly tiny. |
| count++; |
| // If this happens even once, it's ok to report it. |
| print("Failed shuffle $count times"); |
| if (count == 10) fail("Shuffle didn't change order."); |
| } while (true); |
| }); |
| test("Shuffle sublist", (){ |
| List l = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]; |
| List c = l.toList(); |
| shuffle(l, 4, 12); |
| expect(const IterableEquality().equals(l.getRange(0, 4), |
| c.getRange(0, 4)), isTrue); |
| expect(const IterableEquality().equals(l.getRange(12, 16), |
| c.getRange(12, 16)), isTrue); |
| expect(const UnorderedIterableEquality().equals(l.getRange(4, 12), |
| c.getRange(4, 12)), |
| isTrue); |
| |
| }); |
| |
| test("binsearch0", () { |
| expect(binarySearch([], 2), equals(-1)); |
| }); |
| |
| test("binsearch1", () { |
| expect(binarySearch([5], 2), equals(-1)); |
| expect(binarySearch([5], 5), equals(0)); |
| expect(binarySearch([5], 7), equals(-1)); |
| }); |
| |
| test("binsearch3", () { |
| expect(binarySearch([0, 5, 10], -1), equals(-1)); |
| expect(binarySearch([0, 5, 10], 0), equals(0)); |
| expect(binarySearch([0, 5, 10], 2), equals(-1)); |
| expect(binarySearch([0, 5, 10], 5), equals(1)); |
| expect(binarySearch([0, 5, 10], 7), equals(-1)); |
| expect(binarySearch([0, 5, 10], 10), equals(2)); |
| expect(binarySearch([0, 5, 10], 12), equals(-1)); |
| }); |
| |
| test("binsearchCompare0", () { |
| expect(binarySearch([], new C(2), compare: compareC), equals(-1)); |
| }); |
| |
| test("binsearchCompare1", () { |
| var l1 = [new C(5)]; |
| expect(binarySearch(l1, new C(2), compare: compareC), equals(-1)); |
| expect(binarySearch(l1, new C(5), compare: compareC), equals(0)); |
| expect(binarySearch(l1, new C(7), compare: compareC), equals(-1)); |
| }); |
| |
| test("binsearchCompare3", () { |
| var l3 = [new C(0), new C(5), new C(10)]; |
| expect(binarySearch(l3, new C(-1), compare: compareC), equals(-1)); |
| expect(binarySearch(l3, new C(0), compare: compareC), equals(0)); |
| expect(binarySearch(l3, new C(2), compare: compareC), equals(-1)); |
| expect(binarySearch(l3, new C(5), compare: compareC), equals(1)); |
| expect(binarySearch(l3, new C(7), compare: compareC), equals(-1)); |
| expect(binarySearch(l3, new C(10), compare: compareC), equals(2)); |
| expect(binarySearch(l3, new C(12), compare: compareC), equals(-1)); |
| }); |
| |
| test("insertionSortRandom", () { |
| Random random = new Random(); |
| for (int i = 0; i < 25; i++) { |
| List list = new List(i); |
| for (int j = 0; j < i; j++) { |
| list[j] = random.nextInt(25); // Expect some equal elements. |
| } |
| insertionSort(list); |
| for (int j = 1; j < i; j++) { |
| expect(list[j - 1], lessThanOrEqualTo(list[j])); |
| } |
| } |
| }); |
| |
| test("insertionSortSubRanges", () { |
| List l = [6, 5, 4, 3, 2, 1]; |
| insertionSort(l, start: 2, end: 4); |
| expect(l, equals([6, 5, 3, 4, 2, 1])); |
| insertionSort(l, start: 1, end: 1); |
| expect(l, equals([6, 5, 3, 4, 2, 1])); |
| insertionSort(l, start: 4, end: 6); |
| expect(l, equals([6, 5, 3, 4, 1, 2])); |
| insertionSort(l, start: 0, end: 2); |
| expect(l, equals([5, 6, 3, 4, 1, 2])); |
| insertionSort(l, start: 0, end: 6); |
| expect(l, equals([1, 2, 3, 4, 5, 6])); |
| }); |
| |
| test("insertionSortSpecialCases", () { |
| List l = [6, 6, 6, 6, 6, 6]; |
| insertionSort(l); |
| expect(l, equals([6, 6, 6, 6, 6, 6])); |
| |
| l = [6, 6, 3, 3, 0, 0]; |
| insertionSort(l); |
| expect(l, equals([0, 0, 3, 3, 6, 6])); |
| }); |
| |
| test("MergeSortRandom", () { |
| Random random = new Random(); |
| for (int i = 0; i < 250; i += 1) { |
| List list = new List(i); |
| for (int j = 0; j < i; j++) { |
| list[j] = random.nextInt(i); // Expect some equal elements. |
| } |
| mergeSort(list); |
| for (int j = 1; j < i; j++) { |
| expect(list[j - 1], lessThanOrEqualTo(list[j])); |
| } |
| } |
| }); |
| |
| test("MergeSortPreservesOrder", () { |
| Random random = new Random(); |
| // Small case where only insertion call is called, |
| // larger case where the internal moving insertion sort is used |
| // larger cases with multiple splittings, numbers just around a power of 2. |
| for (int size in [8, 50, 511, 512, 513]) { |
| List list = new List(size); |
| // Class OC compares using id. |
| // With size elements with id's in the range 0..size/4, a number of |
| // collisions are guaranteed. These should be sorted so that the "order" |
| // part of the objects are still in order. |
| for (int i = 0; i < size; i++) { |
| list[i] = new OC(random.nextInt(size >> 2), i); |
| } |
| mergeSort(list); |
| OC prev = list[0]; |
| for (int i = 1; i < size; i++) { |
| OC next = list[i]; |
| expect(prev.id, lessThanOrEqualTo(next.id)); |
| if (next.id == prev.id) { |
| expect(prev.order, lessThanOrEqualTo(next.order)); |
| } |
| prev = next; |
| } |
| // Reverse compare on part of list. |
| List copy = list.toList(); |
| int min = size >> 2; |
| int max = size - min; |
| mergeSort(list, start: min, end: max, compare: (a, b) => b.compareTo(a)); |
| prev = list[min]; |
| for (int i = min + 1; i < max; i++) { |
| OC next = list[i]; |
| expect(prev.id, greaterThanOrEqualTo(next.id)); |
| if (next.id == prev.id) { |
| expect(prev.order, lessThanOrEqualTo(next.order)); |
| } |
| prev = next; |
| } |
| // Equals on OC objects is identity, so this means the parts before min, |
| // and the parts after max, didn't change at all. |
| expect(list.sublist(0, min), equals(copy.sublist(0, min))); |
| expect(list.sublist(max), equals(copy.sublist(max))); |
| } |
| }); |
| |
| test("MergeSortSpecialCases", () { |
| for (int size in [511, 512, 513]) { |
| // All equal. |
| List list = new List(size); |
| for (int i = 0; i < size; i++) { |
| list[i] = new OC(0, i); |
| } |
| mergeSort(list); |
| for (int i = 0; i < size; i++) { |
| expect(list[i].order, equals(i)); |
| } |
| // All but one equal, first. |
| list[0] = new OC(1, 0); |
| for (int i = 1; i < size; i++) { |
| list[i] = new OC(0, i); |
| } |
| mergeSort(list); |
| for (int i = 0; i < size - 1; i++) { |
| expect(list[i].order, equals(i + 1)); |
| } |
| expect(list[size - 1].order, equals(0)); |
| |
| // All but one equal, last. |
| for (int i = 0; i < size - 1; i++) { |
| list[i] = new OC(0, i); |
| } |
| list[size - 1] = new OC(-1, size - 1); |
| mergeSort(list); |
| expect(list[0].order, equals(size - 1)); |
| for (int i = 1; i < size; i++) { |
| expect(list[i].order, equals(i - 1)); |
| } |
| |
| // Reversed. |
| for (int i = 0; i < size; i++) { |
| list[i] = new OC(size - 1 - i, i); |
| } |
| mergeSort(list); |
| for (int i = 0; i < size; i++) { |
| expect(list[i].id, equals(i)); |
| expect(list[i].order, equals(size - 1 - i)); |
| } |
| } |
| }); |
| |
| test("Reverse", () { |
| List l = [6, 5, 4, 3, 2, 1]; |
| reverse(l, 2, 4); |
| expect(l, equals([6, 5, 3, 4, 2, 1])); |
| reverse(l, 1, 1); |
| expect(l, equals([6, 5, 3, 4, 2, 1])); |
| reverse(l, 4, 6); |
| expect(l, equals([6, 5, 3, 4, 1, 2])); |
| reverse(l, 0, 2); |
| expect(l, equals([5, 6, 3, 4, 1, 2])); |
| reverse(l, 0, 6); |
| expect(l, equals([2, 1, 4, 3, 6, 5])); |
| }); |
| } |
| |
| class C { |
| final int id; |
| C(this.id); |
| } |
| int compareC(C one, C other) => one.id - other.id; |
| |
| class OC implements Comparable<OC> { |
| final int id; |
| final int order; |
| OC(this.id, this.order); |
| int compareTo(OC other) => id - other.id; |
| String toString() => "OC[$id,$order]"; |
| } |