0x01 实验目的
掌握二叉树的基本概念,二叉树的存储结构使用链表。
0x02 实验内容
- 输入一个完全二叉树的层次遍历字符串,创建这个二叉树,输出这个二叉树的前序遍历字符串、中序遍历字符串、后序遍历字符串、结点数目、二叉树高度(上述每一个结果独立一行显示)。
- 输入二叉树前序序列和中序序列(各元素各不相同),创建这个二叉树,输出该二叉树的后序序列、层次遍历。
0x03 实验过程
层次遍历
判断队列是否为空的条件必须加上,因为队列为空时,有可能会通过q.front()
获取到一些非NULL的奇怪的东西,然后获取其element时会报错。
void levelOrder(binaryTreeNode<E>* node) {
queue<binaryTreeNode<E>*> q;
while (node != NULL) {
if(Level == 0) {
Level++;
cout<<node->element;
if(node->leftChild != NULL) q.push(node->leftChild);
if(node->rightChild != NULL) q.push(node->rightChild);
if(!q.empty()) {
node = q.front();
q.pop();
}else node = NULL;
} else {
cout<<","<<node->element;
if(node->leftChild != NULL) q.push(node->leftChild);
if(node->rightChild != NULL) q.push(node->rightChild);
if(!q.empty()) {
node = q.front();
q.pop();
}else node = NULL;
}
}
}
层次遍历构建二叉树
先将第一个节点放入队列,之后树上每添加一个节点就要将该节点入队列。先进先出的进行添加节点操作,直到node数组空了。
template <class E>
binaryTreeNode<E>* constructTreeByLevelOrder(binaryTreeNode<E> node[],int num) {
queue<binaryTreeNode<E>*> q;
q.push(&node[0]);
int i = 1;
while(i < num) {
binaryTreeNode<E>* current = q.front();
q.pop();
if(i < num) {
current->leftChild = &node[i];
q.push(&node[i]);
}
i++;
if(i < num) {
current->rightChild = &node[i];
q.push(&node[i]);
}
i++;
}
return &node[0];
}
前序遍历和中序遍历构建二叉树
采用递归地形式,依次构建左子树和右子树。利用前序遍历的的第一个节点是头节点,以及在中序遍历中头结点的两侧分别为左子树和右子树这两个性质。
template<class E>
binaryTreeNode<E>* create(binaryTreeNode<E> preorder[], int p, int q, binaryTreeNode<E> inorder[], int i, int j) {
if (p > q) return nullptr;
if (p == q) return &preorder[p];
int k = i;
// 找到根节点在中序遍历序列中的位置
while (preorder[p].element != inorder[k].element) k++;
preorder[p].leftChild = create(preorder, p+1, p+k, inorder, i, k-1);
preorder[p].rightChild = create(preorder, p+k+1, q, inorder, k+1, j);
return &preorder[p];
}
改BUG
0x04 实验源码
#include<bits/stdc++.h>
using namespace std;
int in = 0;
int post = 0;
int Level = 0;
template<class T>
class binaryTreeNode {
public:
T element;
binaryTreeNode<T> *leftChild,*rightChild;
binaryTreeNode() {
leftChild = rightChild = NULL;
}
binaryTreeNode(const T& theElement) : element(theElement) {
leftChild = rightChild = NULL;
}
binaryTreeNode(const T& theElement, binaryTreeNode *theLeftChild, binaryTreeNode *theRightChild):element(theElement) {
leftChild = theLeftChild;
rightChild = theRightChild;
}
};
template<class E>
class linkedBinaryTree {
public:
linkedBinaryTree() {
root = NULL;
treeSize = 0;
}
bool empty() const {
return treeSize == 0;
}
int size() const {
return treeSize;
}
void setSize(int size) {
treeSize = size;
}
void preOrder(binaryTreeNode<E>* node,int level) {
if(node != NULL) {
if(level == 0) {
cout<<node->element;
preOrder(node->leftChild, ++level);
preOrder(node->rightChild, ++level);
} else {
cout<<","<<node->element;
preOrder(node->leftChild, ++level);
preOrder(node->rightChild, ++level);
}
}
}
void inOrder(binaryTreeNode<E>* node) {
if(node != NULL) {
if(node->leftChild == NULL && in == 0) {
cout<<node->element;
in++;
} else {
inOrder(node->leftChild);
cout<<","<<node->element;
inOrder(node->rightChild);
}
}
}
void postOrder(binaryTreeNode<E>* node) {
if(node != NULL) {
if(node->leftChild == NULL && post == 0) {
cout<<node->element;
post++;
} else {
postOrder(node->leftChild);
postOrder(node->rightChild);
cout<<","<<node->element;
}
}
}
void levelOrder(binaryTreeNode<E>* node) {
queue<binaryTreeNode<E>*> q;
while (node != NULL) {
if(Level == 0) {
Level++;
cout<<node->element;
if(node->leftChild != NULL) q.push(node->leftChild);
if(node->rightChild != NULL) q.push(node->rightChild);
if(!q.empty()) {
node = q.front();
q.pop();
}else node = NULL;
} else {
cout<<","<<node->element;
if(node->leftChild != NULL) q.push(node->leftChild);
if(node->rightChild != NULL) q.push(node->rightChild);
if(!q.empty()) {
node = q.front();
q.pop();
}else node = NULL;
}
}
}
int getHeight(binaryTreeNode<E>* node) {
if(node == NULL) return 0;
int h1 = getHeight(node->leftChild);
int h2 = getHeight(node->rightChild);
if(h1 > h2) {
return ++h1;
} else {
return ++h2;
}
}
private:
binaryTreeNode<E> *root;
int treeSize;
};
template <class E>
binaryTreeNode<E>* constructTreeByLevelOrder(binaryTreeNode<E> node[],int num) {
queue<binaryTreeNode<E>*> q;
q.push(&node[0]);
int i = 1;
while(i < num) {
// cout<<"q.front()"<<q.front()<<endl;
// cout<<"&q.front()"<<&q.front()<<endl;
// cout<<"node[0]"<<&node[0]<<endl;
// cout<<"node[0]"<<&node<<endl;
binaryTreeNode<E>* current = q.front();
q.pop();
if(i < num) {
current->leftChild = &node[i];
// cout<<current->leftChild->element<<endl;
// cout<<node[0].leftChild->element<<endl;
q.push(&node[i]);
}
i++;
if(i < num) {
current->rightChild = &node[i];
q.push(&node[i]);
}
i++;
}
return &node[0];
}
template<class E>
binaryTreeNode<E>* create(binaryTreeNode<E> preorder[], int p, int q, binaryTreeNode<E> inorder[], int i, int j) {
if (p > q) return nullptr;
if (p == q) return &preorder[p];
int k = i;
// 找到根节点在中序遍历序列中的位置
while (preorder[p].element != inorder[k].element) k++;
preorder[p].leftChild = create(preorder, p+1, p+k, inorder, i, k-1);
preorder[p].rightChild = create(preorder, p+k+1, q, inorder, k+1, j);
return &preorder[p];
}
int main() {
//两种写法都可以。
//binaryTreeNode<char> *node = new binaryTreeNode<char>[100];
binaryTreeNode<char> node[100];
string s;
cout<<"Input1"<<endl;
cin>>s;
for(int i = 0; i < s.length(); i++) {
binaryTreeNode<char> n(s.at(i));
node[i] = n;
}
linkedBinaryTree<char> tree;
constructTreeByLevelOrder(node,s.length());
tree.setSize(s.length());
// node[0].leftChild = &node[1];
// node[0].rightChild = &node[2];
// cout<<"preOrder"<<endl;
// 记录层数,方便输出逗号
int level = 0;
cout<<"Output1"<<endl;
// cout<<node[0].element<<endl;
// cout<<node[0].leftChild<<endl;
tree.preOrder(&node[0],level);
cout<<endl;
tree.inOrder(&node[0]);
in = 0;
cout<<endl;
tree.postOrder(&node[0]);
post = 0;
cout<<endl;
cout<<tree.size()<<endl;
cout<<tree.getHeight(&node[0])<<endl;
// tree.constructTreeByLevelOrder(node,length);
// tree.inOrder();
// cout<<2<<node[0].element<<node[0].leftChild->element;
cout<<"Input2"<<endl;
string s1,s2;
cin>>s1>>s2;
binaryTreeNode<char> node1[100];
binaryTreeNode<char> node2[100];
for(int i = 0; i < s1.length(); i++) {
binaryTreeNode<char> n(s1.at(i));
node1[i] = n;
}
int noting;
for(int i = 0; i < s2.length(); i++) {
binaryTreeNode<char> n(s2.at(i));
node2[i] = n;
if(s2.at(i) == s1.at(0)) noting = i;
}
//constructTreeByPreOrderAndInOrder(node1, node2, s1.length(), s2.length(), noting);
cout<<"Output2"<<endl;
create(node1, 0, s1.length()-1, node2, 0, s2.length()-1);
// tree.preOrder(&node1[0],level);
// cout<<endl;
// tree.inOrder(&node1[0]);
// cout<<endl;
tree.postOrder(&node1[0]);
cout<<endl;
tree.levelOrder(&node1[0]);
cout<<endl;
cout<<"End"<<endl;
return 0;
}
0x05 错误代码
#include<bits/stdc++.h>
using namespace std;
int in = 0;
int post = 0;
int Level = 0;
template<class T>
class binaryTreeNode {
public:
T element;
binaryTreeNode<T> *leftChild,*rightChild;
binaryTreeNode() {
leftChild = rightChild = NULL;
}
binaryTreeNode(const T& theElement) : element(theElement) {
leftChild = rightChild = NULL;
}
binaryTreeNode(const T& theElement, binaryTreeNode *theLeftChild, binaryTreeNode *theRightChild):element(theElement) {
leftChild = theLeftChild;
rightChild = theRightChild;
}
};
template<class E>
class linkedBinaryTree {
public:
linkedBinaryTree() {
root = NULL;
treeSize = 0;
}
bool empty() const {
return treeSize == 0;
}
int size() const {
return treeSize;
}
void setSize(int size) {
treeSize = size;
}
void preOrder(binaryTreeNode<E>* node,int level) {
if(node != NULL) {
if(level == 0) {
cout<<node->element;
preOrder(node->leftChild, ++level);
preOrder(node->rightChild, ++level);
} else {
cout<<","<<node->element;
preOrder(node->leftChild, ++level);
preOrder(node->rightChild, ++level);
}
}
}
void inOrder(binaryTreeNode<E>* node) {
if(node != NULL) {
if(node->leftChild == NULL && in == 0) {
cout<<node->element;
in++;
} else {
inOrder(node->leftChild);
cout<<","<<node->element;
inOrder(node->rightChild);
}
}
}
void postOrder(binaryTreeNode<E>* node) {
if(node != NULL) {
if(node->leftChild == NULL && post == 0) {
cout<<node->element;
post++;
} else {
postOrder(node->leftChild);
postOrder(node->rightChild);
cout<<","<<node->element;
}
}
}
void levelOrder(binaryTreeNode<E>* node) {
queue<binaryTreeNode<E>*> q;
while (node != NULL) {
if(Level == 0) {
Level++;
cout<<node->element;
if(node->leftChild != NULL) q.push(node->leftChild);
if(node->rightChild != NULL) q.push(node->rightChild);
node = q.front();
q.pop();
} else {
cout<<","<<node->element;
if(node->leftChild != NULL) q.push(node->leftChild);
if(node->rightChild != NULL) q.push(node->rightChild);
node = q.front();
q.pop();
}
}
}
int getHeight(binaryTreeNode<E>* node) {
if(node == NULL) return 0;
int h1 = getHeight(node->leftChild);
int h2 = getHeight(node->rightChild);
if(h1 > h2) {
return ++h1;
} else {
return ++h2;
}
}
private:
binaryTreeNode<E> *root;
int treeSize;
};
template <class E>
binaryTreeNode<E>* constructTreeByLevelOrder(binaryTreeNode<E> node[],int num) {
queue<binaryTreeNode<E>*> q;
q.push(&node[0]);
int i = 1;
while(i < num) {
// cout<<"q.front()"<<q.front()<<endl;
// cout<<"&q.front()"<<&q.front()<<endl;
// cout<<"node[0]"<<&node[0]<<endl;
// cout<<"node[0]"<<&node<<endl;
binaryTreeNode<E>* current = q.front();
q.pop();
if(i < num) {
current->leftChild = &node[i];
// cout<<current->leftChild->element<<endl;
// cout<<node[0].leftChild->element<<endl;
q.push(&node[i]);
}
i++;
if(i < num) {
current->rightChild = &node[i];
q.push(&node[i]);
}
i++;
}
return &node[0];
}
template <class E>
//左子树的实现
binaryTreeNode<E>* soul(int noting, binaryTreeNode<E> node1[], binaryTreeNode<E> node2[]) {
int index1 = 100;
int index2 = 100;
for(int i = 1; i <= noting; i++) {
for(int j = noting; j >= 0; j--) {
if(node1[i].element == node2[j].element) {
index1 = index2;
index2 = j;
cout<<"index1"<<index1<<endl;
cout<<"index2"<<index2<<endl;
}
}
if(index1 > index2) {
node1[i-1].leftChild = &node1[i];
} else {
// cout<<"Yes"<<endl;
for(int j = noting; j >= 0; j--) {
if(node1[i].element == node2[j].element) {
for(int k = noting; k >= 0; k--) {
if(node2[j-1].element == node1[k].element) {
node1[k].rightChild = &node1[i];
}
}
}
}
}
}
return &node1[0];
}
template <class E>
binaryTreeNode<E>* constructTreeByPreOrderAndInOrder(binaryTreeNode<E> node1[], binaryTreeNode<E> node2[], int num1, int num2, int noting) {
soul(noting, node1, node2);
int temp;
//获取下一个左子树区间
for(int i = noting + 1; i < num1; i++) {
if(node2[i].element == node1[noting+1].element) {
temp = noting;
noting = i;
}
}
do {
//重复操作,直到剩下最后一个元素,或者不剩下元素,退出循环
int num = 0;
binaryTreeNode<char> node3[100];
binaryTreeNode<char> node4[100];
for(int i = temp + 1; i <= noting; i++) {
node3[num] = node1[i];
node4[num] = node2[i];
num++;
}
soul(noting, node3, node4);
for(int i = noting + 1; i < num1; i++) {
if(node2[i].element == node1[noting+1].element) {
temp = noting;
noting = i;
}
}
} while(noting + 1 != num1 - 1 && noting + 1 != num1);
//如果剩一个元素
if(noting + 1 == num1 - 1) node2[num1 - 1].rightChild = &node2[num1];
return &node1[0];
}
int main() {
//binaryTreeNode<char> *node = new binaryTreeNode<char>[100];
binaryTreeNode<char> node[100];
string s;
cout<<"Input"<<endl;
cin>>s;
for(int i = 0; i < s.length(); i++) {
binaryTreeNode<char> n(s.at(i));
node[i] = n;
}
linkedBinaryTree<char> tree;
constructTreeByLevelOrder(node,s.length());
tree.setSize(s.length());
// node[0].leftChild = &node[1];
// node[0].rightChild = &node[2];
// cout<<"preOrder"<<endl;
// 记录层数,方便输出逗号
int level = 0;
cout<<"Output"<<endl;
// cout<<node[0].element<<endl;
// cout<<node[0].leftChild<<endl;
tree.preOrder(&node[0],level);
cout<<endl;
tree.inOrder(&node[0]);
in = 0;
cout<<endl;
tree.postOrder(&node[0]);
post = 0;
cout<<endl;
cout<<tree.size()<<endl;
cout<<tree.getHeight(&node[0])<<endl;
// tree.constructTreeByLevelOrder(node,length);
// tree.inOrder();
// cout<<2<<node[0].element<<node[0].leftChild->element;
cout<<"Input2"<<endl;
string s1,s2;
cin>>s1>>s2;
binaryTreeNode<char> node1[100];
binaryTreeNode<char> node2[100];
for(int i = 0; i < s1.length(); i++) {
binaryTreeNode<char> n(s1.at(i));
node1[i] = n;
}
int noting;
for(int i = 0; i < s2.length(); i++) {
binaryTreeNode<char> n(s2.at(i));
node2[i] = n;
if(s2.at(i) == s1.at(0)) noting = i;
}
constructTreeByPreOrderAndInOrder(node1, node2, s1.length(), s2.length(), noting);
cout<<"Output2"<<endl;
tree.preOrder(&node1[0],level);
cout<<endl;
tree.inOrder(&node1[0]);
cout<<endl;
tree.postOrder(&node1[0]);
cout<<endl;
tree.levelOrder(&node1[0]);
cout<<endl;
return 0;
}