public static void AddRange_MultipleKeys_FormsCorrectBST()
{
var tree = new BinarySearchTree <int>();
tree.AddRange(new List <int> {
5, 3, 4, 2
});
var rootNode = tree.Search(5);
Assert.AreEqual(5, rootNode !.Key);
Assert.AreEqual(3, rootNode !.Left !.Key);
Assert.IsNull(rootNode !.Right);
var threeNode = tree.Search(3);
Assert.AreEqual(3, threeNode !.Key);
Assert.AreEqual(2, threeNode !.Left !.Key);
Assert.AreEqual(4, threeNode !.Right !.Key);
var twoNode = tree.Search(2);
Assert.IsNull(twoNode !.Left);
Assert.IsNull(twoNode !.Right);
var fourNode = tree.Search(4);
Assert.IsNull(fourNode !.Left);
Assert.IsNull(fourNode !.Right);
}
public void BSTUseTest()
{
string filepath = @"..\..\..\Resources\Communist.txt";
string[] words = File.ReadAllText(filepath, Encoding.UTF8).Split(' ');
Console.WriteLine($"Word count: {words.Length}");
Stopwatch sw = new Stopwatch();
sw.Start();
BinarySearchTree <string, int> bst = new BinarySearchTree <string, int>();
foreach (string word in words)
{
int val = bst.Search(word.ToLower());
bst.Insert(word.ToLower(), ++val);
}
if (bst.Contains("unite"))
{
Console.WriteLine($"unite: {bst.Search("unite")}");
}
else
{
Console.WriteLine("No word 'unite' in the file.");
}
sw.Stop();
Console.WriteLine($"BST, time:{sw.ElapsedMilliseconds} ms");
Assert.IsTrue(bst.Search("unite") == 1);
}
public static void Constructor_UseCustomComparer_FormsCorrectTree()
{
var cmpFunc = Comparer <string> .Create((x, y) => x.Length - y.Length);
var tree = new BinarySearchTree <string>(cmpFunc);
var elems = new[] { "z", "yy", "vvv", "bbbb", "fffff", "pppppp" };
tree.AddRange(elems);
Assert.IsNotNull(tree.Search("vvv"));
Assert.AreEqual("bbbb", tree.Search("vvv") !.Right !.Key);
}
public static void Remove_NodesWithTwoChildren_CorrectlyRemovesNodes()
{
var tree = new BinarySearchTree <int>();
tree.AddRange(new List <int> {
5, 3, 4, 2, 7, 6, 8
});
var sevenRemoveResult = tree.Remove(7);
Assert.IsTrue(sevenRemoveResult);
Assert.IsNull(tree.Search(7));
Assert.IsNull(tree.Search(6) !.Left);
Assert.IsNotNull(tree.Search(6) !.Right);
Assert.AreEqual(6, tree.Count);
}
public static void Remove_RemoveRoot_CorrectlyRemovesRoot()
{
var tree = new BinarySearchTree <int>();
tree.Add(5);
tree.Remove(5);
Assert.AreEqual(0, tree.Count);
Assert.IsNull(tree.Search(5));
tree.AddRange(new List <int> {
5, 4, 6
});
tree.Remove(5);
Assert.AreEqual(2, tree.Count);
Assert.IsNull(tree.Search(5));
Assert.IsNotNull(tree.Search(4));
Assert.IsNotNull(tree.Search(6));
Assert.AreEqual(6, tree.Search(4) !.Right !.Key);
}
public static void Remove_NodesWithOneChild_CorrectlyRemovesNodes()
{
var tree = new BinarySearchTree <int>();
tree.AddRange(new List <int> {
5, 3, 4, 2, 7, 6, 8
});
tree.Remove(4);
var threeRemoveResult = tree.Remove(3);
Assert.IsTrue(threeRemoveResult);
Assert.IsNull(tree.Search(3));
Assert.IsNull(tree.Search(2) !.Left);
Assert.IsNull(tree.Search(2) !.Right);
Assert.AreEqual(5, tree.Count);
tree.Remove(6);
var sevenRemoveResult = tree.Remove(7);
Assert.IsTrue(sevenRemoveResult);
Assert.IsNull(tree.Search(7));
Assert.IsNull(tree.Search(8) !.Left);
Assert.IsNull(tree.Search(8) !.Right);
Assert.AreEqual(3, tree.Count);
}
public static void Search_MultipleKeys_FindsAllKeys()
{
var tree = new BinarySearchTree <int>();
tree.AddRange(new List <int> {
5, 3, 4, 2, 7, 6, 8
});
Assert.AreEqual(2, tree.Search(2) !.Key);
Assert.AreEqual(3, tree.Search(3) !.Key);
Assert.AreEqual(4, tree.Search(4) !.Key);
Assert.AreEqual(5, tree.Search(5) !.Key);
Assert.AreEqual(6, tree.Search(6) !.Key);
Assert.AreEqual(7, tree.Search(7) !.Key);
Assert.AreEqual(8, tree.Search(8) !.Key);
}
public void Search_NonExistingElement_ShouldReturnEmptyTree()
{
var bst = new BinarySearchTree <int>();
bst.Insert(2);
bst.Insert(1);
bst.Insert(3);
var result = bst.Search(5);
var nodes = new List <int>();
result.EachInOrder(nodes.Add);
var expectedNodes = new int[] { };
CollectionAssert.AreEqual(expectedNodes, nodes);
Assert.AreEqual(expectedNodes.Length, result.Count());
}
public void Search_ExistingElement_ShouldReturnSubTree()
{
var bst = new BinarySearchTree <int>();
bst.Insert(20);
bst.Insert(10);
bst.Insert(5);
bst.Insert(15);
bst.Insert(17);
bst.Insert(30);
bst.Insert(25);
bst.Insert(35);
var result = bst.Search(10);
var nodes = new List <int>();
result.EachInOrder(nodes.Add);
var expectedNodes = new int[] { 5, 10, 15, 17 };
CollectionAssert.AreEqual(expectedNodes, nodes);
}
public static void Remove_LeafNodes_CorrectlyRemovesNodes()
{
var tree = new BinarySearchTree <int>();
tree.AddRange(new List <int> {
5, 3, 4, 2, 7, 6, 8
});
var twoRemoveResult = tree.Remove(2);
Assert.IsTrue(twoRemoveResult);
Assert.IsNull(tree.Search(2));
Assert.IsNull(tree.Search(3) !.Left);
Assert.IsNotNull(tree.Search(3) !.Right);
Assert.AreEqual(6, tree.Count);
var fourRemoveResult = tree.Remove(4);
Assert.IsTrue(fourRemoveResult);
Assert.IsNull(tree.Search(4));
Assert.IsNull(tree.Search(3) !.Left);
Assert.IsNull(tree.Search(3) !.Right);
Assert.AreEqual(5, tree.Count);
}