C语言实现二叉树的搜索及相关算法示例

 #include #include using namespace std; class tree_node{ public: int key; tree_node *left; tree_node *right; int tag; tree_node(){ key = 0; left = right = NULL; tag = 0; } ~tree_node(){} }; void visit(int value){ printf("%d\n", value); } // 插入 tree_node * insert_tree(tree_node *root, tree_node* node){ if (!node){ return root; } if (!root){ root = node; return root; } tree_node * p = root; while (p){ if (node->key key){ if (p->left){ p = p->left; } else{ p->left = node; break; } } else{ if (p->right){ p = p->right; } else{ p->right = node; break; } } } return root; } // 查询key所在node tree_node* search_tree(tree_node* root, int key){ tree_node * p = root; while (p){ if (key key){ p = p->left; } else if (key > p->key){ p = p->right; } else{ return p; } } return NULL; } // 创建树 tree_node* create_tree(tree_node *t, int n){ tree_node * root = t; for (int i = 1; ileft){ return NULL; } tree_node* p = root->left; while (p->right){ p = p->right; } return p; } // 节点后继 tree_node* tree_suc(tree_node* root){ if (!root->right){ return NULL; } tree_node* p = root->right; while (p->left){ p = p->left; } return p; } // 中序遍历 void tree_walk_mid(tree_node *root){ if (!root){ return; } tree_walk_mid(root->left); visit(root->key); tree_walk_mid(root->right); } // 中序遍历非递归 void tree_walk_mid_norecursive(tree_node *root){ if (!root){ return; } tree_node* p = root; stack s; while (!s.empty() || p){ while (p){ s.push(p); p = p->left; } if (!s.empty()){ p = s.top(); s.pop(); visit(p->key); p = p->right; } } } // 前序遍历 void tree_walk_pre(tree_node *root){ if (!root){ return; } visit(root->key); tree_walk_pre(root->left); tree_walk_pre(root->right); } // 前序遍历非递归 void tree_walk_pre_norecursive(tree_node *root){ if (!root){ return; } stack s; tree_node* p = root; s.push(p); while (!s.empty()){ tree_node *node = s.top(); s.pop(); visit(node->key); if (node->right){ s.push(node->right); } if (node->left){ s.push(node->left); } } } // 后序遍历 void tree_walk_post(tree_node *root){ if (!root){ return; } tree_walk_post(root->left); tree_walk_post(root->right); visit(root->key); } // 后序遍历非递归 void tree_walk_post_norecursive(tree_node *root){ if (!root){ return; } stack s; s.push(root); while (!s.empty()){ tree_node * node = s.top(); if (node->tag != 1){ node->tag = 1; if (node->right){ s.push(node->right); } if (node->left){ s.push(node->left); } } else{ visit(node->key); s.pop(); } } } // 层级遍历非递归 void tree_walk_level_norecursive(tree_node *root){ if (!root){ return; } queue q; tree_node* p = root; q.push(p); while (!q.empty()){ tree_node *node = q.front(); q.pop(); visit(node->key); if (node->left){ q.push(node->left); } if (node->right){ q.push(node->right); } } } // 拷贝树 tree_node * tree_copy(tree_node *root){ if (!root){ return NULL; } tree_node* newroot = new tree_node(); newroot->key = root->key; newroot->left = tree_copy(root->left); newroot->right = tree_copy(root->right); return newroot; } // 拷贝树 tree_node * tree_copy_norecursive(tree_node *root){ if (!root){ return NULL; } tree_node* newroot = new tree_node(); newroot->key = root->key; stack s1, s2; tree_node *p1 = root; tree_node *p2 = newroot; s1.push(root); s2.push(newroot); while (!s1.empty()){ tree_node* node1 = s1.top(); s1.pop(); tree_node* node2 = s2.top(); s2.pop(); if (node1->right){ s1.push(node1->right); tree_node* newnode = new tree_node(); newnode->key = node1->right->key; node2->right = newnode; s2.push(newnode); } if (node1->left){ s1.push(node1->left); tree_node* newnode = new tree_node(); newnode->key = node1->left->key; node2->left = newnode; s2.push(newnode); } } return newroot; } int main(){ tree_node T[6]; for (int i = 0; i <6; i++){ T[i].key = i*2; } T[0].key = 5; tree_node* root = create_tree(T, 6); //tree_walk_mid(root); //tree_walk_mid_norecursive(root); //tree_walk_pre(root); //tree_walk_pre_norecursive(root); //tree_walk_post(root); //tree_walk_post_norecursive(root); //tree_walk_level_norecursive(root); visit(search_tree(root, 6)->key); visit(tree_pre(root)->key); visit(tree_suc(root)->key); //tree_node* newroot = tree_copy_norecursive(root); //tree_walk_mid(newroot); return 0; }