1 #include <stdio.h>
2
3 typedef int ElementType;
4
5 struct BinarySearchTreeNode
6 {
7 ElementType Element;
8 struct BinarySearchTreeNode *Left;
9 struct BinarySearchTreeNode *Right;
10 };
11
12 //be careful with the names of the node and struct
13 struct BinarySearchTreeNode* BinaryTreeLCA(struct BinarySearchTreeNode* TreeRoot,struct BinarySearchTreeNode* TreeNode_1,struct BinarySearchTreeNode* TreeNode_2)
14 {
15 if(TreeRoot==NULL || TreeRoot==TreeNode_1 || TreeRoot==TreeNode_2)
16 {
17 return TreeRoot;
18 }
19
20 struct BinarySearchTreeNode* NewLeft = BinaryTreeLCA(TreeRoot -> Left,TreeNode_1,TreeNode_2);
21 struct BinarySearchTreeNode* NewRight = BinaryTreeLCA(TreeRoot -> Right,TreeNode_1,TreeNode_2);
22
23 if(NewLeft && NewRight)
24 {
25 return TreeRoot;
26 }
27
28 return NewLeft == NULL ? NewRight : NewLeft;
29 }
30
31 int BinarySearchTreeNodeFindLevel(struct BinarySearchTreeNode *TreeRoot,struct BinarySearchTreeNode *NodeToBeFind)
32 {
33 if(TreeRoot == NULL || NodeToBeFind == NULL)
34 {
35 return -1;
36 }
37 if(TreeRoot -> Element == NodeToBeFind -> Element)
38 {
39 return 0;
40 }
41
42 int Level = BinarySearchTreeNodeFindLevel(TreeRoot -> Left,NodeToBeFind);
43 if(Level == -1)
44 {
45 Level = BinarySearchTreeNodeFindLevel(TreeRoot -> Right,NodeToBeFind);
46 }
47 if(Level != -1)
48 {
49 return (Level+1);
50 }
51 return -1;
52 }
53
54 int BinarySearchTreeNodeDistance(struct BinarySearchTreeNode* TreeRoot,struct BinarySearchTreeNode* TreeNode_1,struct BinarySearchTreeNode* TreeNode_2)
55 {
56 struct BinarySearchTreeNode* TwoNodeLCA = BinaryTreeLCA(TreeRoot,TreeNode_1,TreeNode_2);
57
58 int LCADistance = BinarySearchTreeNodeFindLevel(TreeRoot,TwoNodeLCA);
59 int Node_1Distance = BinarySearchTreeNodeFindLevel(TreeRoot,TreeNode_1);
60 int Node_2Distance = BinarySearchTreeNodeFindLevel(TreeRoot,TreeNode_2);
61
62 return (Node_1Distance + Node_2Distance - 2 * LCADistance);
63 }
64
65 int main()
66 {
67 //int result = BinarySearchTreeNodeDistance(TreeRoot,BinarySearchTreeNodeFind(-1,TreeRoot),BinarySearchTreeNodeFind(-1,TreeRoot));
68 //printf("%d\n",result);
69 return 0;
70 }
