A step-by-step illustration of Binary Search Tree (Exact Match) to help you walk through a series of operations. Illustration is accompanied by actual code with bold line indicating the current operation.

1. Binary Search Tree
- Exact match
Illustrated walk through

2. Node structure
public class Node
{
public int Value;
public Node Left;
public Node Right;
}
Value
Left
Right

3. Sample tree
5
3
1
10
4
7
12

4. Find Exact Match
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}
Base Case:
return when beyond a leaf
return a node found
Recursively search left or
right subtree

5. node
target
5
3
1
10
4
7
12
public Node FindExact( Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}
7

6. node
target
5
3
node == null
is false
1
10
4
7
12
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}
7

7. node
target
5
3
5 == 7
is false
1
10
4
7
12
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}
7

8. node
target
5
3
5<7
is true
1
10
4
7
12
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}
7

9. node
target
5
3
1
7
10
4
7
12
Call Stack for 5
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}

10. target
5
node
3
1
7
10
4
7
12
Call Stack for 10
Call Stack for 5
public Node FindExact( Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}

11. target
5
node
3
node == null
is false
1
7
10
4
7
12
Call Stack for 10
Call Stack for 5
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}

12. target
5
node
3
1
10 == 7
is false
7
10
4
7
12
Call Stack for 10
Call Stack for 5
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}

13. target
5
node
3
1
10 < 7
is false
7
10
4
7
12
Call Stack for 10
Call Stack for 5
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}

14. target
5
node
3
else (10 > 7)
is true
1
7
10
4
7
12
Call Stack for 10
Call Stack for 5
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}

15. target
5
3
1
node
7
10
4
7
12
Call Stack for 7
Call Stack for 10
Call Stack for 5
public Node FindExact( Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}

16. node == null
is false
target
5
3
1
node
7
10
4
7
12
Call Stack for 7
Call Stack for 10
Call Stack for 5
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}

17. 7 == 7
is true
3
1
node
7
target
5
10
4
7
12
Call Stack for 7
Call Stack for 10
Call Stack for 5
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
We found an
exact match!
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}

18. target
5
3
7
10
Call Stack for 7
1
node
4
7
12
Call Stack for 10
Call Stack for 5
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}
7

19. target
5
node
3
1
7
10
4
7
12
Call Stack for 10
7
Call Stack for 5
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}

20. target
5
node
3
1
7
10
4
7
12
Call Stack for 5
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
if (node.Value == target) {
return node;
}
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}
7

21. target
5
3
1
7
10
4
7
12
public Node FindExact(Node node, int target) {
if (node == null) {
return null;
}
The caller of the
if (node.Value ==
FindExactreturn node;
receives
node 7}
target) {
if (node.Value < target) {
return FindExact(node.Right, target);
}
else {
return FindExact(node.Left, target);
}
}
7