1 #include <memory>//智能指针头文件
2 #include <random>//随机数头文件
3 #include <iostream>
4 #include <algorithm>
5 #include <ctime>//time头文件
6
7 template<class T>
8 struct node
9 {
10 T key;
11 unsigned weight;
12 std::shared_ptr<node<T>> lchild, rchild, parent;
13 node(T key, unsigned weight, std::shared_ptr<node<T>> lchild = nullptr,
14 std::shared_ptr<node<T>> rchild = nullptr, std::shared_ptr<node<T>> parent = nullptr):
15 key(key)
16 {
17 this->weight = weight;
18 this->lchild = lchild;
19 this->rchild = rchild;
20 this->parent = parent;
21 }
22 };
23
24 template<class T>
25 class Treap
26 {
27 private:
28 std::shared_ptr<node<T>> root;
29 std::default_random_engine generator;
30 std::uniform_int_distribution<int> dis;
31 void left_rotation(std::shared_ptr<node<T>> a)
32 {
33 if (a == nullptr) return;
34
35 std::shared_ptr<node<T>> b = a->lchild;
36 if (b == nullptr) return;
37
38 if (b->rchild != nullptr)
39 {
40 a->lchild = b->rchild;
41 b->rchild->parent = a;
42 }
43 else
44 a->lchild = nullptr;//
45
46 b->parent = a->parent;
47 if (a->parent == nullptr)
48 root = b;
49 else
50 {
51 if (a->parent->lchild == a)
52 a->parent->lchild = b;
53 else
54 a->parent->rchild = b;
55 }
56
57 b->rchild = a;
58 a->parent = b;
59 }
60 void right_rotation(std::shared_ptr<node<T>> a)
61 {
62 if (a == nullptr) return;
63
64 std::shared_ptr<node<T>> b = a->rchild;
65 if (b == nullptr) return;
66
67 if (b->lchild != nullptr)
68 {
69 a->rchild = b->lchild;
70 b->lchild->parent = a;
71 }
72 else
73 a->rchild = nullptr;
74
75 b->parent = a->parent;
76 if (a->parent == nullptr)
77 root = b;
78 else
79 {
80 if (a->parent->lchild == a)
81 a->parent->lchild = b;
82 else
83 a->parent->rchild = b;
84 }
85
86 b->lchild = a;
87 a->parent = b;
88 }
89 public:
90 Treap() :generator(time(nullptr)), dis(0, 100000)
91 {
92 root = nullptr;
93 }
94 void insert(T key)
95 {
96 std::shared_ptr<node<T>> tmp = std::make_shared<node<T>>(key, dis(generator));
97 std::shared_ptr<node<T>> ptr = root;
98 if (ptr == nullptr)
99 {
100 root = tmp;
101 return;
102 }
103
104 while (true)
105 {
106 if (key <= ptr->key)
107 {
108 if (ptr->lchild == nullptr) break;
109 ptr = ptr->lchild;
110 }
111 else
112 {
113 if (ptr->rchild == nullptr) break;
114 ptr = ptr->rchild;
115 }
116 }
117
118 if (key <= ptr->key)
119 ptr->lchild = tmp;
120 else
121 ptr->rchild = tmp;
122 tmp->parent = ptr;
123
124 while (ptr != nullptr)
125 {
126 if (tmp->weight < ptr->weight)
127 {
128 if (ptr->lchild == tmp)
129 {
130 left_rotation(ptr);
131 ptr = tmp->parent;
132 }
133 else
134 {
135 right_rotation(ptr);
136 ptr = tmp->parent;
137 }
138 }
139 else
140 break;
141 }
142 }
143 void earse(T key)
144 {
145 std::shared_ptr<node<T>> ptr = root;
146 while (ptr != nullptr)
147 {
148 if (key == ptr->key)
149 break;
150 else if (key < ptr->key)
151 ptr = ptr->lchild;
152 else
153 ptr = ptr->rchild;
154 }
155 if (ptr == nullptr) return;
156 while (true)
157 {
158 if (ptr->lchild == nullptr || ptr->rchild == nullptr)
159 {
160 if (ptr->lchild == nullptr && ptr->rchild == nullptr)
161 {
162 if (ptr->parent == nullptr) root = nullptr;
163 else
164 {
165 if (ptr->parent->lchild == ptr)
166 ptr->parent->lchild = nullptr;
167 else
168 ptr->parent->rchild = nullptr;
169 }
170 }
171 else if (ptr->lchild == nullptr)
172 {
173 if (ptr->parent == nullptr)
174 root = ptr->rchild;
175 else
176 {
177 if (ptr->parent->lchild == ptr)
178 ptr->parent->lchild = ptr->rchild;
179 else
180 ptr->parent->rchild = ptr->rchild;
181 }
182 ptr->rchild->parent = ptr->parent;
183 }
184 else
185 {
186 if (ptr->parent == nullptr)
187 root = ptr->lchild;
188 else
189 {
190 if (ptr->parent->lchild == ptr)
191 ptr->parent->lchild = ptr->lchild;
192 else
193 ptr->parent->rchild = ptr->lchild;
194 }
195 ptr->lchild->parent = ptr->parent;
196 }
197 return;
198 }
199 else
200 {
201 if (ptr->lchild->weight <= ptr->rchild->weight)
202 left_rotation(ptr);
203 else
204 right_rotation(ptr);
205 }
206 }
207 }
208 };
