1 #include <memory> 2 3 template<class T> 4 struct rb_node 5 { 6 T key; 7 bool color;//true red | false black 8 std::shared_ptr<rb_node> lchild, rchild, parent; 9 10 rb_node(T key, bool color = true, std::shared_ptr<rb_node> lchild = nullptr, 11 std::shared_ptr<rb_node> rchild = nullptr, std::shared_ptr<rb_node> parent = nullptr) 12 :key(key)//此处不能使用this：现在对象还没被构建起来 13 { 14 //赋值，初始化在初始化列表中执行 15 this->color = color; 16 this->lchild = lchild; 17 this->rchild = rchild; 18 this->parent = parent; 19 } 20 }; 21 22 template<class T> 23 class rb_tree 24 { 25 private: 26 std::shared_ptr<rb_node<T>> root; 27 std::shared_ptr<rb_node<T>> nil;//叶节点 28 void left_rotation(std::shared_ptr<rb_node<T>> a) 29 { 30 if (a == nullptr) return; 31 std::shared_ptr<rb_node<T>> b = a->rchild; 32 if (b == nullptr) return; 33 if (b->lchild != nullptr) 34 b->lchild->parent = a; 35 a->rchild = b->lchild; 36 37 if (a->parent == nil) 38 root = b;//rbtree的root以nil为父节点 39 else 40 { 41 if (a->parent->lchild == a) 42 a->parent->lchild = b; 43 else 44 a->parent->rchild = b; 45 } 46 b->parent = a->parent; 47 48 b->lchild = a; 49 a->parent = b; 50 } 51 void right_rotation(std::shared_ptr<rb_node<T>> a) 52 { 53 if (a == nullptr) return; 54 std::shared_ptr<rb_node<T>> b = a->lchild; 55 if (b == nullptr) return; 56 if (b->rchild != nullptr) 57 b->rchild->parent = a; 58 a->lchild = b->rchild; 59 60 if (a->parent == nil) 61 root = b; 62 else 63 { 64 if (a->parent->lchild == a) 65 a->parent->lchild = b; 66 else 67 a->parent->rchild = b; 68 } 69 b->parent = a->parent; 70 71 b->rchild = a; 72 a->parent = b; 73 } 74 75 public: 76 rb_tree() 77 { 78 root = nullptr; 79 T key; 80 nil = std::make_shared<rb_node<T>>(key, false); 81 } 82 void insert(T key) 83 { 84 std::shared_ptr<rb_node<T>> tmp = std::make_shared<rb_node<T>>(key, true, nil, nil, nil); 85 std::shared_ptr<rb_node<T>> ptr = root; 86 87 //情况1：树为空 88 if (ptr == nullptr) 89 { 90 tmp->color = false; 91 root = tmp; 92 return; 93 } 94 while (true) 95 { 96 if (key <= ptr->key) 97 { 98 if (ptr->lchild == nil) break; 99 ptr = ptr->lchild; 100 } 101 else 102 { 103 if (ptr->rchild == nil) break; 104 ptr = ptr->rchild; 105 } 106 } 107 108 if (key <= ptr->key) 109 ptr->lchild = tmp; 110 else 111 ptr->rchild = tmp; 112 tmp->parent = ptr; 113 114 while(true) 115 { 116 if (ptr == nil)//注意root可能被情况三修改为red，记得加特判 117 { 118 tmp->color = false; 119 root = tmp; 120 return; 121 } 122 123 //情况2：插入节点的父节点为黑色 124 if (!ptr->color) return; 125 126 /*情况3：插入节点的父节点和叔节点都存在且都为红色*/ 127 if (ptr->parent->lchild->color && ptr->parent->rchild->color) 128 { 129 ptr->parent->color = true; 130 ptr->parent->lchild->color = false; 131 ptr->parent->rchild->color = false; 132 133 tmp = ptr->parent; 134 ptr = tmp->parent; 135 continue; 136 } 137 if (ptr->parent->lchild == ptr) 138 { 139 //情况4：右旋 140 if (tmp == ptr->lchild) 141 { 142 ptr->parent->color = true; 143 ptr->color = false; 144 right_rotation(ptr->parent); 145 return; 146 } 147 else 148 { 149 //情况5：左旋 + 右旋 150 left_rotation(ptr); 151 tmp = ptr; 152 ptr = tmp->parent; 153 continue; 154 } 155 } 156 else 157 { 158 //情况4：左旋 159 if (tmp == ptr->rchild) 160 { 161 ptr->parent->color = true; 162 ptr->color = false; 163 left_rotation(ptr->parent); 164 return; 165 } 166 else 167 { 168 //情况5：右旋+左旋 169 right_rotation(ptr); 170 tmp = ptr; 171 ptr = tmp->parent; 172 continue; 173 } 174 } 175 } 176 } 177 void earse(T key) 178 { 179 //待续 180 } 181 };