日撸 Java 三百行的 CPP 实现(21-30天, 树与二叉树)
Day 21-30
This part is the CPP implementation of 日撸 Java 三百行（21-30天，树与二叉树）.
Day 21: 二叉树的深度遍历的递归实现
实现一个 BinaryCharTree 类, 并手动构建一个二叉树. 使用递归实现二叉树的前序遍历、中序遍历、后序遍历. 使用递归实现获取二叉树的层数、节点数函数.
#include output:
Preorder visit: a b d f g c e
In-order visit: b f d g a e c
Post-order visit: f g d b e c a
The depth is: 4
The number of nodes is: 7
Day 22: 二叉树的存储
对于任意一棵二叉树, 我们可以将其转换为满二叉树来存储. 以 Day 21 的数据为例, 将其转换为满二叉树并编号的结果如图所示:
其中, N 表示空节点. 设根结点的编号为 1 1 1, 对于任意一个节点 i i i, 其左儿子的编号为 i × 2 i\times2 i×2 右儿子的编号为 i × 2 + 1 i\times2+1 i×2+1. 然后用两个数组分别存储节点的值和节点的编号.
value array: [A, B, C, D, E, F, G]
index array: [1, 2, 3, 5, 6, 10, 11]
#include output:
Preorder visit: A B D F G C E
In-order visit: B F D G A E C
Post-order visit: F G D B E C A
The depth is: 4
The number of nodes is: 7
value array: A B C D E F G
index array: 1 2 3 5 6 10 11
Day 23: 使用具有通用性的队列
使用 CPP 类模板实现一个循环队列, 替换 Day 22 使用的 std::vector 和 std::queue.
#include output:
Preorder visit: A B D F G C E
In-order visit: B F D G A E C
Post-order visit: F G D B E C A
The depth is: 4
The number of nodes is: 7
value array: A B C D E F G
index array: 1 2 3 5 6 10 11
Day 24: 二叉树的建立
今天的内容相当于 Day 22 的逆过程, 根据层次遍历的结果构建二叉树.
#include output:
Preorder visit: A B D F G C E
In-order visit: B F D G A E C
Post-order visit: F G D B E C A
The depth is: 4
The number of nodes is: 7
value array: A B C D E F G
index array: 1 2 3 5 6 10 11
Preorder visit: A B D F G C E
In-order visit: B F D G A E C
Post-order visit: F G D B E C A
Day 25: 二叉树的深度遍历的栈实现(中序)
Part 1 栈的实现
template<typename T>
class MyStack
{
public:
const int MAX_LENGTH = 10;
int depth;
T* data;
MyStack()
{
this->depth = 0;
this->data = new T[MAX_LENGTH];
}
std::string to_string()
{
std::stringstream ss;
for (int i = 0; i < this->depth; i ++)
{
ss << this->data[i];
}
return ss.str();
}
bool push(T value)
{
if (this->depth == MAX_LENGTH)
{
std::cout << "Stack full." << std::endl;
return false;
}
this->data[this->depth] = value;
this->depth ++;
return true;
}
void pop()
{
if (this->depth == 0)
{
std::cout << "Stack empty." << std::endl;
return;
}
this->depth --;
}
T top()
{
return this->data[this->depth - 1];
}
bool empty()
{
if (this->depth == 0) return true;
return false;
}
};
Part 2 中序遍历
#include output:
Preorder visit: A B D F G C E
In-order visit: B F D G A E C
Post-order visit: F G D B E C A
The depth is: 4
The number of nodes is: 7
value array: A B C D E F G
index array: 1 2 3 5 6 10 11
Preorder visit: A B D F G C E
In-order visit: B F D G A E C
Post-order visit: F G D B E C A
In-order visit by stack: B F D G A E C
Day 26: 二叉树的深度遍历的栈实现(前序和后序)
#include output:
Preorder visit: A B D F G C E
In-order visit: B F D G A E C
Post-order visit: F G D B E C A
The depth is: 4
The number of nodes is: 7
value array: A B C D E F G
index array: 1 2 3 5 6 10 11
Preorder visit: A B D F G C E
In-order visit: B F D G A E C
Post-order visit: F G D B E C A
In-order visit by stack: B F D G A E C
Preorder visit by satck: A B D F G C E
Post-order visit by stack: F G D B E C A
Day 27: Hanoi 塔问题
#include output:
a->c a->b c->b a->c b->a b->c a->c
Day 28: Huffman 编码(节点定义与文件读取)
Day 29: Huffman 编码(建树)
Day 30: Huffman 编码(编码与解码)
以下为 Day 28、Day 29 和 Day 30 的全部代码
#include output:
1 1 9 0 0
2 2 12 0 0
3 1 9 0 0
4 1 10 0 0
5 1 10 0 0
6 2 12 0 0
7 1 11 0 0
8 1 11 0 0
9 2 13 1 3
10 2 13 4 5
11 2 14 7 8
12 4 14 2 6
13 4 15 9 10
14 6 15 11 12
15 10 0 13 14
the Huffman Code of each char:
g:000 i:110 m:001 n:010 o:011 s:111 u:100 y:101
the Huffman Code of the string:
001110111111110010000101011100
The decode of the Huffman Code:
missingyou
Data compression ratio: 24%