二叉树两节点距离

 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 }