问题描述
我正在构建一棵红黑树作为学校项目我已经完成了代码，但出于某种原因，当我运行程序测试用例时，我在 nilNode 为黑色时出错，我不知道为什么
程序代码
#ifndef RBTREE_HPP
#define RBTREE_HPP
#include <string>
#include <vector>
#define FMT_HEADER_ONLY
#include <fmt/format.h>
#include <stack>
enum class Colour { RED,BLACK };
namespace std {
std::string to_string(const std::string& str) { return str; }
std::string to_string(const Colour& colour) {
return (colour == Colour::RED) ? "RED" : "BLACK";
}
} // namespace std
// Remember to always do a make clean / refresh build when using templates
template <typename V>
class RBReader;
template <typename T>
class RBTree {
friend RBReader<T>;
private:
struct Node {
Node* parent = nullptr;
Node* leftChild = nullptr;
Node* rightChild = nullptr;
Colour colour = Colour::RED;
T element = T();
};
Node* root = nullptr;
Node* nilNode = nullptr;
int GzAddNode(std::string& nodes,std::string& connections,const Node* curr,size_t to);
int GzAddChild(std::string& nodes,const Node* child,size_t from,size_t to,const std::string& color);
template <typename V>
std::string GzNode(size_t to,const V& what,const std::string& style,const std::string& fillColor,const std::string& fontColor);
std::string GzConnection(size_t from,const std::string& color,const std::string& style);
public:
RBTree();
~RBTree();
RBTree(const RBTree& other) = delete;
RBTree& operator=(const RBTree& other) = delete;
RBTree(RBTree&& other) = delete;
RBTree& operator=(RBTree&& other) = delete;
bool addNode(const T& element);
void rightRotate(Node* node);
void leftRotate(Node* node);
bool deleteNode(const T &element);
bool find(const T& element);
const T& min();
const T& max();
std::vector<T> inorder();
int height();
std::vector<T> pathFromroot(const T& element);
std::string ToGraphviz();
};
template <typename T>
RBTree<T>::RBTree() {}
template <typename T>
RBTree<T>::~RBTree() {}
template <typename T>
bool RBTree<T>::addNode(const T& element) {
// if tree is empty,return true
if (root == nilNode) {
root = new Node();
root->element = element;
return true;
}
// if element is already in tree,return false
if (find(element)) {
return false;
}
// otherwise,insert element
Node* curr = root;
Node* parent = nullptr;
Node* child = nullptr;
while (curr != nilNode) {
parent = curr;
if (element < curr->element) {
child = curr->leftChild;
} else {
child = curr->rightChild;
}
if (child == nilNode) {
break;
}
curr = child;
}
Node* newNode = new Node();
newNode->element = element;
newNode->parent = parent;
if (child == nilNode) {
child = newNode;
} else {
child->parent = newNode;
}
if (element < parent->element) {
parent->leftChild = child;
} else {
parent->rightChild = child;
}
return true;
}
template <typename T>
bool RBTree<T>::deleteNode(const T& element) {
// delete node from rb tree and return true if node exists,else return false
Node* curr = root;
while (curr != nullptr) {
if (element < curr->element) {
curr = curr->leftChild;
} else if (element > curr->element) {
curr = curr->rightChild;
} else {
break;
}
}
if (curr == nullptr) {
return false;
}
if (curr->leftChild == nullptr || curr->rightChild == nullptr) {
Node* child = curr->leftChild == nullptr ? curr->rightChild : curr->leftChild;
if (child != nullptr) {
child->parent = curr->parent;
}
if (curr->parent == nullptr) {
root = child;
nilNode = child;
} else {
if (curr->parent->leftChild == curr) {
curr->parent->leftChild = child;
} else {
curr->parent->rightChild = child;
}
}
delete curr;
} else {
Node* successor = curr->rightChild;
while (successor->leftChild != nullptr) {
successor = successor->leftChild;
}
curr->element = successor->element;
delete successor;
}
return true;
}
template <typename T>
bool RBTree<T>::find(const T& element) {
// find node in rb tree and return true if node exists,else return false
Node* curr = root;
while (curr != nullptr) {
if (element < curr->element) {
curr = curr->leftChild;
} else if (element > curr->element) {
curr = curr->rightChild;
} else {
return true;
}
}
return false;
}
template <typename T>
const T& RBTree<T>::min() {
static T tmp;
// return minimum element in rb tree
if (root == nullptr) {
tmp = T();
return tmp;
}
Node* curr = root;
while (curr->leftChild != nullptr) {
curr = curr->leftChild;
}
tmp = curr->element;
return tmp;
}
template <typename T>
const T& RBTree<T>::max() {
static T tmp;
// return maximum element in rb tree
if (root == nullptr) {
tmp = T();
return tmp;
}
Node* curr = root;
while (curr->rightChild != nullptr) {
curr = curr->rightChild;
}
tmp = curr->element;
return tmp;
}
template <typename T>
std::vector<T> RBTree<T>::inorder() {
// return vector of elements in rb tree in order
std::vector<T> result;
if (root == nullptr) {
return result;
}
std::stack<Node*> st;
Node* curr = root;
while (curr != nullptr || !st.empty()) {
while (curr != nullptr) {
st.push(curr);
curr = curr->leftChild;
}
curr = st.top();
st.pop();
result.push_back(curr->element);
curr = curr->rightChild;
}
return result;
}
template <typename T>
int RBTree<T>::height() {
// return height of rb tree
if (root == nullptr) {
return 0;
}
std::stack<Node*> st;
st.push(root);
int h = 0;
while (!st.empty()) {
Node* curr = st.top();
st.pop();
if (curr->leftChild != nullptr) {
st.push(curr->leftChild);
}
if (curr->rightChild != nullptr) {
st.push(curr->rightChild);
}
h++;
}
return h;
}
template <typename T>
std::vector<T> RBTree<T>::pathFromroot(const T& element) {
// return vector of elements in rb tree from root to element
std::vector<T> result;
if (root == nullptr) {
return result;
}
std::stack<Node*> st;
Node* curr = root;
while (curr != nullptr || !st.empty()) {
while (curr != nullptr) {
st.push(curr);
curr = curr->leftChild;
}
curr = st.top();
st.pop();
result.push_back(curr->element);
if (curr->element == element) {
break;
}
curr = curr->rightChild;
}
return result;
}
template <typename T>
std::string RBTree<T>::ToGraphviz() // Member function of the AVLTree class
{
std::string toReturn = std::string("digraph {\n");
if (root != nullptr &&
root != nilNode) // root is a pointer to the root node of the tree
{
std::string nodes;
std::string connections = "\t\"Root\" -> 0;\n";
GzAddNode(nodes,connections,root,0);
toReturn += nodes;
toReturn += connections;
}
toReturn += "}";
return toReturn;
}
template <typename T>
int RBTree<T>::GzAddNode(std::string& nodes,size_t to) {
size_t from = to;
nodes += GzNode(from,curr->element,"filled",curr->colour == Colour::RED ? "tomato" : "black",curr->colour == Colour::RED ? "black" : "white");
to = GzAddChild(nodes,curr->leftChild,from,++to,"blue");
to = GzAddChild(nodes,curr->rightChild,"gold");
return to;
}
template <typename T>
int RBTree<T>::GzAddChild(std::string& nodes,const std::string& color) {
if (child != nilNode) {
connections += GzConnection(from,to,color,"");
to = GzAddNode(nodes,child,to);
} else if (child == nullptr) {
nodes += GzNode(to,"null","orange","black");
connections += GzConnection(from,"","");
} else {
nodes += GzNode(to,child->element,"invis","");
connections += GzConnection(from,"invis");
}
return to;
}
template <typename T>
template <typename V>
std::string RBTree<T>::GzNode(size_t to,const std::string& fontColor) {
return fmt::format(
"\t{} [label=\"{}\",fillcolor=\"{}\",fontcolor=\"{}\",style=\"{}\"]\n",what,fillColor,fontColor,style);
}
template <typename T>
std::string RBTree<T>::GzConnection(size_t from,const std::string& style) {
return fmt::format("\t{} -> {} [color=\"{}\" style=\"{}\"]\n",style);
}
#endif
我尝试做的 - 更改节点结构中的颜色 - 改变 nill 节点的颜色 -改变根节点的颜色
我遇到的错误
-------------------------------------------------------------------------------
Scenario: Some simple cases
Given: An empty tree
Then: The nil node should be black
-------------------------------------------------------------------------------
test/testsRedBlacktree.cpp:29
...............................................................................
test/testsRedBlacktree.cpp:29: Failed:
REQUIRE( reader.nilIsBlack() )
with expansion:
false
with message:
GraphViz representation:
---
digraph {
}
===============================================================================
test cases: 1 | 1 Failed
assertions: 3 | 2 passed | 1 Failed
解决方法
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