@Test
public void reverseOrderTraversal_EmptyTree() {
BinarySearchTree<Integer> bst = new BinarySearchTree<Integer>();
assertTrue(
"Expected an empty list for an empty tree",
TreeUtil.reverseLevelOrderTraversal(bst.getRoot()).isEmpty());
}
@Test
public void testLevelOrderTraversal_EmptyTree() {
BinarySearchTree<Integer> bst = new BinarySearchTree<Integer>();
List<List<Integer>> lst = TreeUtil.levelOrderTraversal(bst.getRoot());
assertNotNull("Expecting an empty list in case root node is null", lst);
assertTrue("Expecting an empty list in case root node is null", lst.isEmpty());
}
@Test
public void testDFS_RandomBST() {
int MAX_ITER = 100;
int MAX_SIZE = 10;
for (int iter = 0; iter < MAX_ITER; iter++) {
List<Integer> lstVals = new ArrayList<Integer>();
BinarySearchTree<Integer> bst = generateRandomIntTree(MAX_SIZE, lstVals, true);
Comparator<Integer> comp = bst.getComp();
String msg =
"Searching for values "
+ lstVals
+ " in tree with values inserted in the same order : "
+ lstVals;
for (int val : lstVals) {
BinaryTreeNode<Integer> node = TreeUtil.dfs(bst.getRoot(), val, comp);
assertNotNull(msg, node);
assertEquals(msg, val, node.getVal().intValue());
}
// Testing for values that do not exist
for (int i = 0; i < 100; i++) {
if (!lstVals.contains(i)) {
assertNull(msg, TreeUtil.dfs(bst.getRoot(), i, comp));
}
}
}
}
private static BinarySearchTree<Integer> getSimpleBST() {
BinarySearchTree<Integer> bst =
new BinarySearchTree<Integer>(new BinaryTreeNode<Integer>(2), getIntComparator());
bst.getRoot().setLeft(new BinaryTreeNode<Integer>(1));
bst.getRoot().setRight(new BinaryTreeNode<Integer>(3));
return bst;
}
@Test
public void testLevelOrderTraversal_SingleNode() {
BinarySearchTree<Integer> bst = getTreeWithRootNode();
List<List<Integer>> lst = TreeUtil.levelOrderTraversal(bst.getRoot());
String msg = "Expecting [ [1] ]";
assertNotNull(msg, lst);
assertEquals(msg, 1, lst.size());
assertEquals(msg, 1, lst.get(0).size());
assertEquals(msg, 1, lst.get(0).get(0).intValue());
}
@Test
public void reverseOrderTraversal_SingleNode() {
BinarySearchTree<Integer> bst = new BinarySearchTree<Integer>();
bst.setComp(getIntComparator());
bst.insert(1);
List<Integer> lst = TreeUtil.reverseLevelOrderTraversal(bst.getRoot());
assertTrue("Expected a non empty list for tree with single node", !lst.isEmpty());
assertTrue("Expecting size of the list to be 1", lst.size() == 1);
assertEquals(1, (int) lst.get(0));
}
@Test
public void testDFS_TreeWithSingleNode() {
BinarySearchTree<Integer> bst = getTreeWithRootNode();
Comparator<Integer> comp = getIntComparator();
String msg =
"Searching for values 0 to 9 in tree with values inserted in the same order : [ 1 ]";
for (int i = 0; i < 10; i++) {
if (i == 1) {
BinaryTreeNode<Integer> node = TreeUtil.dfs(bst.getRoot(), i, comp);
assertNotNull(msg, node);
assertEquals(msg, 1, node.getVal().intValue());
} else {
assertNull(TreeUtil.bfs(bst.getRoot(), i, comp));
}
}
}
@Test
public void testLevelOrderTraversal_SimpleBST() {
BinarySearchTree<Integer> bst = getSimpleBST();
List<List<Integer>> lst = TreeUtil.levelOrderTraversal(bst.getRoot());
String msg = "Expecting [ [2], [ 1, 3] ]";
List<List<Integer>> expectedValLst = new ArrayList<List<Integer>>();
expectedValLst.add(new ArrayList<Integer>());
expectedValLst.add(new ArrayList<Integer>());
expectedValLst.get(0).add(2);
expectedValLst.get(1).add(1);
expectedValLst.get(1).add(3);
assertNotNull(msg, lst);
assertEquals(msg, expectedValLst.size(), lst.size());
for (int index = 0; index < expectedValLst.size(); index++) {
List<Integer> eLst = expectedValLst.get(index);
List<Integer> aLst = lst.get(index);
assertEquals(msg, eLst.size(), aLst.size());
for (int index1 = 0; index1 < eLst.size(); index1++) {
assertEquals(msg, eLst.get(index1), aLst.get(index1));
}
}
}
@Test
public void reverseOrderTraversal_SimpleTestCase() {
BinarySearchTree<Integer> bst = new BinarySearchTree<Integer>();
bst.setComp(getIntComparator());
bst.insert(100);
bst.insert(50);
bst.insert(150);
bst.insert(30);
bst.insert(70);
bst.insert(60);
bst.insert(120);
bst.insert(130);
bst.insert(170);
bst.insert(160);
List<Integer> lst = TreeUtil.reverseLevelOrderTraversal(bst.getRoot());
assertTrue("Expected a non empty list for tree with single node", !lst.isEmpty());
int[] expectedVals = new int[] {60, 130, 160, 30, 70, 120, 170, 50, 150, 100};
assertTrue("Expecting size of the list to be 3", lst.size() == expectedVals.length);
for (int index = 0; index < expectedVals.length; index++) {
assertEquals(expectedVals[index], (int) lst.get(index));
}
}
private static BinarySearchTree<Integer> generateRandomIntTree(
int size, List<Integer> lstVals, boolean isUnique) {
if (lstVals == null) {
throw new IllegalArgumentException(
"This methods expects an empty set to output all the added values in this set");
} else {
// do nothing here. go ahead
}
lstVals.clear();
BinarySearchTree<Integer> retBst = new BinarySearchTree<Integer>();
retBst.setComp(getIntComparator());
Random random = new Random();
int maxValue = size * 10;
int val = -1;
for (int iter = 0; iter < size; iter++) {
do {
val = random.nextInt(maxValue);
} while (isUnique && lstVals.contains(val));
lstVals.add(val);
retBst.insert(val);
}
return retBst;
}
@Test
public void testLevelOrderTraversal_HandCraftedTree() {
BinarySearchTree<Integer> bst = new BinarySearchTree<Integer>();
bst.setComp(getIntComparator());
List<List<Integer>> expectValList = new ArrayList<List<Integer>>();
bst.insert(100);
int level = 0;
expectValList.add(new ArrayList<Integer>());
expectValList.get(level).add(100);
level++;
expectValList.add(new ArrayList<Integer>());
bst.insert(50);
expectValList.get(level).add(50);
bst.insert(150);
expectValList.get(level).add(150);
level++;
expectValList.add(new ArrayList<Integer>());
bst.insert(30);
expectValList.get(level).add(30);
bst.insert(130);
expectValList.get(level).add(130);
bst.insert(180);
expectValList.get(level).add(180);
List<List<Integer>> lst = TreeUtil.levelOrderTraversal(bst.getRoot());
String msg = "Input Tree : [ 100, 50, 150, 30, #, 130, 180 ]";
assertNotNull(msg, lst);
assertEquals(msg, expectValList.size(), lst.size());
for (int index = 0; index < expectValList.size(); index++) {
List<Integer> eLst = expectValList.get(index);
List<Integer> aLst = lst.get(index);
assertEquals(msg, eLst.size(), aLst.size());
for (int index1 = 0; index1 < eLst.size(); index1++) {
assertEquals(msg, eLst.get(index1), aLst.get(index1));
}
}
}