1 //查找
2 void Search(node *root, int x)
3 {
4 if(root == NULL)
5 {
6 printf("search failed\n");
7 return;
8 }
9 if(x == root->data)
10 printf("%d\n", root->data);
11 else if(x < root->data)
12 Search(root->lchild, x);
13 else if(x > root->data)
14 Search(root->data)
15 Search(root->rchild, x);
16 }
17
18 //插入
19 void Insert(node *root, int x)
20 {
21 if(root == NULL)
22 {
23 root = newNode(x); //新建结点
24 return;
25 }
26 if(x == root->data)
27 return;
28 else if(x > root->data)
29 Insert(root->rchild, x);
30 else if(x < root->data)
31 Insert(root->lchild, x);
32 }
33
34 //建立
35 node* Create(int data[], int n)
36 {
37 node *root = NULL;
38 for(int i=0; i<n; i++)
39 Insert(root, data[i]);
40
41 return root;
42 }
43
44 //删除
45
46 //寻找前驱
47 node* FindMax(node *root)
48 {
49 while(root->rchild != NULL)
50 root = root->rchild;
51 return root;
52 }
53
54 //寻找后继
55 node* FindMin(node *root)
56 {
57 while(root->lchild != NULL)
58 root = root->lchild;
59 return root;
60 }
61
62 //删除结点root
63 void Delete(node *&root, int x)
64 {
65 if(root == NULL)
66 return;
67 if(root->data == x)
68 {
69 if(root->lchild==NULL & root->rchild==NULL) //叶子结点直接删除即可
70 root = NULL;
71 else if(root->lchild != NULL)
72 {
73 node *pre = FindMax(root->lchild); //寻找左子树的最大值（最右结点）
74 root->data = pre->data; //与被删除结点替换
75 Delete(root->lchild, pre->data); //删除替换后的结点
76 }
77 else if(root->rchild != NULL)
78 {
79 node *pre = FindMin(root->rchild); //寻找右子树的最小值（最左结点）
80 root->data = pre->data;
81 Delete(root->rchild, pre->data);
82 }
83 }
84 else if(x < root->data)
85 Delete(root->lchild, x);
86 else if(x > root->data)
87 Delete(root->rchild, x);
88 }
1 #include<stdio.h>
2 const int M = 10;
3 const int data[M] = {6,12,18,4,5,7,16,19,17,9};
4
5 struct node
6 {
7 int data;
8 node *lchild, *rchild;
9 };
10
11 node* FindMax(node *root)
12 {
13 while(root->rchild->rchild)
14 root = root->rchild;
15 return root;
16 }
17
18 node *FindMin(node *root)
19 {
20 while(root->lchild->lchild)
21 root = root->lchild;
22 return root;
23 }
24
25 void BST(node *&root, int x)
26 {
27 if(!root)
28 {
29 root = new node;
30 root->data = x;
31 root->lchild = NULL;
32 root->rchild = NULL;
33 return;
34 }
35 if(x == root->data)
36 {
37 if(!root->lchild && !root->rchild)
38 root = NULL;
39 else if(root->lchild)
40 {
41 node *pre;
42 if(root->lchild->rchild == NULL)
43 {
44 pre = root->lchild;
45 root->lchild = pre->lchild;
46 }
47 else
48 {
49 node *fa = FindMax(root->lchild);
50 pre = fa->rchild;
51 fa->rchild = pre->lchild;
52 }
53 root->data = pre->data;
54 delete(pre);
55 }
56 else if(root->rchild)
57 {
58 node *pre;
59 if(root->rchild->lchild == NULL)
60 {
61 pre = root->rchild;
62 root->rchild = pre->rchild;
63 }
64 else
65 {
66 node *fa = FindMin(root->rchild);
67 pre = fa->rchild;
68 fa->rchild = pre->lchild;
69 }
70 root->data = pre->data;
71 delete(pre);
72 }
73 }
74 else if(x < root->data)
75 BST(root->lchild, x);
76 else if(x > root->data)
77 BST(root->rchild, x);
78 }
79
80 void Traverse(node *root)
81 {
82 if(root == NULL)
83 return;
84 Traverse(root->lchild);
85 printf("%d ", root->data);
86 Traverse(root->rchild);
87 }
88
89 node* Create()
90 {
91 node *root = NULL;
92 for(int i=0; i<M; i++)
93 BST(root, data[i]);
94
95 return root;
96 }
97
98 int main()
99 {
100 #ifdef ONLINE_JUDGE
101 #else
102 freopen("Test.txt", "r", stdin);
103 #endif // ONLINE_JUDGE
104
105 node *root = Create();
106 Traverse(root);
107 printf("\n");
108 BST(root, 6);
109 Traverse(root);
110
111 return 0;
112 }