1 #include <iostream>
2 #include <cstdlib>
3 using namespace std;
4 struct node
5 {
6 int v;
7 int df;
8 node * left_c;
9 node * right_c;
10 };
11 void right_rotate(node *&ptr)
12 {
13 if (ptr->right_c->df==-1)
14 {
15 node * child = ptr->right_c;
16 ptr->right_c = child ->left_c;
17 child ->left_c = ptr;
18 ptr->df = 0;
19 child->df = 0;
20 ptr = child;
21 }
22 else
23 {
24 node * child = ptr->right_c;
25 node * g_child = child ->left_c;
26 child ->left_c = g_child ->right_c;
27 ptr->right_c = g_child -> left_c;
28 g_child->left_c = ptr;
29 g_child->right_c = child;
30 switch(g_child->df)
31 {
32 case 0:ptr->df = 0;child->df =0;break;
33 case 1:ptr->df = 0; child->df = -1;g_child->df = 0;break;
34 case -1:ptr->df = 1; child->df = 0;g_child->df = 0;break;
35 }
36 ptr = g_child;
37 }
38 }
39 void left_rotate(node *&ptr)
40 {
41 if (ptr->left_c->df==1) // LL型旋转
42 {
43 // ptr 的左二子成为老子 ptr成为其右儿子
44 node * child = ptr->left_c;
45 ptr->left_c = child ->right_c;
46 child ->right_c = ptr;
47 ptr->df = 0;
48 child->df = 0;
49 ptr = child;
50 }
51 else // LR型旋转
52 {
53 node * child = ptr->left_c; // L儿子
54 node * g_child = child ->right_c; // LR 孙子
55
56 // 孙子的两个儿子 根据 二叉查找树定义 分别给 child 和 ptr
57 child ->right_c = g_child ->left_c;
58 ptr->left_c = g_child -> right_c;
59 //孙子成为老子
60 g_child->right_c = ptr;
61 g_child->left_c = child;
62 //根据孙子的df调整各点
63 switch(g_child->df)
64 {
65 case 0:ptr->df = 0;child->df =0;break;
66 case -1:ptr->df = 0; child->df = 1;g_child->df = 0;break;
67 case 1:ptr->df = -1; child->df = 0;g_child->df = 0;break;
68 }
69 ptr = g_child;
70 }
71 }
72 void avl_insert(node * &ptr ,int t,bool &if_b)
73 {
74 if (ptr == NULL) // 新节点
75 {
76 if_b = false;
77 ptr = (node *)malloc(sizeof(node));
78 ptr->df = 0;
79 ptr->left_c = NULL;
80 ptr->right_c = NULL;
81 ptr->v = t;
82 }
83 else if (t > ptr->v) // 与左子树完全对称
84 {
85 avl_insert(ptr->right_c,t,if_b);
86 if (!if_b)
87 {
88 switch(ptr->df)
89 {
90 case 0:ptr->df = -1;break;
91 case 1:ptr->df = 0;if_b = true; break;
92 case -1:right_rotate(ptr);if_b = true;break;
93 }
94 }
95 }
96 else if (t < ptr->v) // 在左子树中加入
97 {
98 avl_insert(ptr->left_c,t,if_b);
99 if (!if_b)
100 {
101 switch(ptr->df)
102 {
103 case 0:ptr->df = 1;break;//不平衡
104 case -1:ptr->df = 0;if_b = true; break; //恰好调节平衡
105 case 1:left_rotate(ptr);if_b = true;break; //旋转后调节平衡
106 }
107 }
108 }
109 else // 找到元素
110 {
111 cout <<t <<"cunzai"<<endl;
112 if_b = true;
113 return;
114 }
115 }
116 void proorder(node * ptr) //中序遍历
117 {
118 if (ptr ==NULL) return;
119 proorder(ptr->left_c);
120 cout << ptr->v <<" ";
121 proorder(ptr->right_c);
122 }
123 int main()
124 {
125 int N;
126 cin >> N;
127 node* root = NULL;
128 bool if_b = false;
129 for (int i = 1 ; i<=N; i++)
130 {
131 int x;
132 cin >> x;
133 if_b = false;
134 avl_insert(root,x,if_b);
135 }
136 proorder(root);
137 cout <<endl;
138 }
