每周专业学习周记-1

Posted 2020-11-28 xxxxxxxxxx

每周专业学习周记-1

标签（空格分隔）： 周记

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说明：接下来的每一周都将会跟新我的专业学习周记，内容包括代码+总结。目前主要除了课程内的《数据结构与算法》课程之外，还有Python语言学习，Python作为现在比较热门并且易入门的编程语言，学习它无论是用作工具还是提升自己都会有很好的帮助，教材使用【美】《Python编程从入门到实践》。
接下来的每周我将会持续更新我的学习情况。

数据结构篇

#include <stdio.h>
#include <stdlib.h>
#define DataType char
int count;
typedef struct Node
{
    DataType data;
    struct Node* LChild;
    struct Node* RChild;
}BiTNode,*BiTree;

void GreateBiTree(BiTree *root)
{
    char ch;
    ch = getchar();
    if(ch==‘#‘)
        *root = NULL;
    else
    {
        *root = (BiTree)malloc(sizeof(BiTNode));
        (*root)->data = ch;
        GreateBiTree(&((*root)->LChild));
        GreateBiTree(&((*root)->RChild));
    }
    
}

void PreOrder(BiTree root)
{
    
    if(root==NULL)
        return;
    else
    {
        printf("%c",root->data);
        PreOrder(root->LChild);
        PreOrder(root->RChild);
    }
}

void InOrder(BiTree root)
{
    if(root == NULL)
        return;
    else
    {
        InOrder(root->LChild);
        printf("%c",root->data);
        InOrder(root->RChild);
    }
}

void PostOrder(BiTree root)
{
    if(root == NULL)
        return;
    else
    {
        PostOrder(root->LChild);
        PostOrder(root->RChild);
        printf("%c",root->data);
    }
}

void PreLeaf(BiTree root)
{
    if (root!=NULL)
    {
        if (root->LChild==NULL && root->RChild==NULL)
            printf("%c",root->data);
        PreLeaf(root->LChild);
        PreLeaf(root->RChild);
    }

}

void InLeaf(BiTree root)
{
    if (root!=NULL)
    {
        InLeaf(root->LChild);
        if (root->LChild==NULL && root->RChild==NULL)
            printf("%c",root->data);
        InLeaf(root->RChild);
    }
    
}

void PostLeaf(BiTree root)
{
    if (root!=NULL)
    {
        PostLeaf(root->LChild);
        PostLeaf(root->RChild);
        if (root->LChild==NULL && root->RChild==NULL)
            printf("%c",root->data);
    }
}

void LeafCount(BiTree root)
{
    if (root!=NULL)
    {
        LeafCount(root->LChild);
        LeafCount(root->RChild);
        if (root->LChild==NULL && root->RChild==NULL)
            count++;
    }
}

int LeafCountB(BiTree root)
{
    int Count;
    if (root==NULL)
        Count = 0;
    else if(root->LChild==NULL && root->RChild==NULL)
        Count = 1;
    else
        Count = LeafCountB(root->LChild) + LeafCountB(root->RChild);
    return (Count);
}

int PostTreeDepth(BiTree root)
{
    int left,right,max;
    if (root!=NULL)
    {
        left = PostTreeDepth(root->LChild);
        right = PostTreeDepth(root->RChild);
        max = left>right?left:right;
        return(max+1);
    }
    else
        return(0);
}

int PreTreeDepth(BiTree root)
{
    int depth=0,h=1;
    h++;
    if(root != NULL) 
    {
        
        if (h>depth) depth = h;
        PreTreeDepth(root->LChild);
        PreTreeDepth(root->RChild);
    }
    return(h);
}

int main()
{
    BiTree root;
    GreateBiTree(&root);
    printf("先序遍历是：");
    PreOrder(root);
    printf("
中序遍历是：");
    InOrder(root);
    printf("
后序遍历是：");
    PostOrder(root);
    printf("
前序遍历打印叶子节点：");
    PreLeaf(root);
    printf("
中序遍历打印叶子节点：");
    InLeaf(root);
    printf("
后序遍历打印叶子节点：");
    PostLeaf(root);
    
    LeafCount(root);
    printf("
全局变量统计叶子节点个数为：");
    printf("%d",count);
    printf("
分治算法统计叶子节点个数为：");
    printf("%d",LeafCountB(root));
    
    printf("
后续遍历求二叉树的高度为：");
    printf("%d",PostTreeDepth(root));
    printf("
先序遍历求二叉树高度的递归算法：");
    printf("%d ",PreTreeDepth(root));
    return 0;
}

数据结构小结

以上代码题目分别是：
（1）按照课本中二叉树的链式存储的定义，实现二叉树的链式定义，实现以下二叉树的创建（二叉树中存储的数据为字符类型数据，输入数据时候空子树用“#”）：root指向根结点
（2）分别采用先序、中序、后序输出上述二叉树的结点数据信息。
（3）-（7）选作
（3）假设二叉树采用链接存储结构进行存储，root指向根结点，输出二叉树中的叶子结点。（先序，中序，后序）
（4）假设二叉树采用链接存储结构进行存储，root指向根结点，统计叶子结点数目(全局变量，分治算法)。
（5）假设二叉树采用链接存储结构进行存储，root指向根结点，求二叉树的高度。
递归算法的理解始终是有些难度，需要一层一层的慢慢通过栈的方式出栈入栈.

Python篇

#4.11遍历整个列表
magicians = [‘alice‘,‘david‘,‘carolian‘]
for magician in magicians:
	print(magician)
#4.1.2 在for循环中执行更多的操作
magicians = [‘alice‘,‘david‘,‘carolian‘]
for magician in magicians:
	print(magician.title()+",that was a great trick!")
	print("I can‘t wait to see your next trick, "+magician.title()+".
")
#4.1.3在for循环之后执行一些操作
magicians = [‘alice‘,‘david‘,‘carolian‘]
for magician in magicians:
	print(magician.title()+",that was a great trick!")
	print("I can‘t wait to see your next trick, "+magician.title()+".
")
print("Thank you,everyone.That was a great magic show!")

#4.2.1 忘记缩进
# magicians = [‘alice‘,‘david‘,‘carolian‘]
# for maician in magicians:
# print("I can‘t wait to see your next trick, "+magician.title()+".
")
#IndentationError: expected an indented block 这个提示就是没有缩进

#4.2.2 忘记缩进额外的代码行
magicians = [‘alice‘,‘david‘,‘carolian‘]
for magician in magicians:
	print(magician.title()+",taht was a great trick!")
print("I can‘t wait to see your next trick, "+magician.title()+".
")

#4.2.3 不必要的缩进
# message = "Hello python world!"
# 	print(message)
#IndentationError: unexpected indent 这个提示是有不必要的缩进

#4.2.5 遗漏了冒号
# magicians = [‘alice‘,‘david‘,‘carolian‘]
# for magician in magicians
# 	print(magician)
#SyntaxError: invalid syntax 语法错误，这里是for后面没有加封号

#4-1 披萨
pizzas = [‘durian pizza‘,‘apple pizza‘,‘banana pizza‘]
for pizza in pizzas:
	print("I like "+pizza+".")

print("I really love banana pozza!")

#4-2 动物
dogs = [‘teddy‘,‘husky‘,‘chinese rural dog‘]
for dog in dogs :
	print(dog.title()+" would like a great pet.")
print("Any of these animals would make a great pet!")

#4.3.1 使用range()函数
for value in range(1,5):
	print(value)

for value in range(1,6):
	print(value," ",end="")
print()
#4.3.2 用range()创建数字列表
numbers = list(range(1,6))
print(numbers)
#设置步长
even_numbers = (list(range(1,11,2)))
print(even_numbers)

squares = []
for value in range(1,11):
	square = value**2
	squares.append(square) 
print(squares)

squares = []
for value in range(1,11):
	squares.append(value**2)
print(squares)

#4.3.3 对数字列表执行简单的统计计算
digits = [10,2,3,4,5,6,65]
print(sum(digits),max(digits),min(digits))

#4.3.4 列表解析
squares = [value**2 for value in range(1,21)]
print(squares)

#4-3 数到二十
for value in range(1,21):
	print(value,end=" ")
print()
#4-4 一百万
# for value in range(1,1000000):
# 	print(value)

#4-5 计算1-1000000
#

#4-6 奇数
for value in range(1,20,2):
	print(value,end=" ")
print()

#4-7 三的倍数
number = [value for value in range(3,30,3)]
for num in number:
	print(num,end=" ")
print()
number = [value for value in range(1,30)]
for value in number:
	if value % 3 == 0:
		print(value,end=" ")
print()
#4-8 立方
number = []
for num in range(1,11):
	number.append(num**3)
for value in number:
	print(value,end=" ")

#4-9 立方解析
print()
number = [value**3 for value in range(1,11)]
print(number)

#4.4.1 切片
players = [‘charles‘,‘martina‘,‘michael‘,‘florence‘,‘eli‘] 
print(players[0:3])
print(players[1:4])
#如果没有指定第一个索引，python将自动从头开始
print(players[:4])
#同样的如果没有指定后一个索引，Python将自动从第一个索引开始访问后面的所有列表值
print(players[2:])
#如果想要输出最后三名队员的名字
print(players[-3:])
#如果想要输出倒数第三个队员之前的名字
print(players[:-3])

#4.4.2 遍历切片
players = [‘charles‘,‘martina‘,‘michael‘,‘florence‘,‘eli‘]
print(‘Here are the first three players on my team.‘)
for player in players:
	print(player.title(),end=",")

#4.4.2 复制列表
my_foods = [‘pizza‘,‘falafel‘,‘carrot cake‘]
friend_foods = my_foods[:]
print("
my favorite food are:")
print(my_foods)

print("my friend‘s favorite food are:")
print(friend_foods)
#这是从my_food里面提取了一个切片

#用切片的方式复制才能
my_foods = [‘pizza‘,‘falafel‘,‘carrot cake‘]
friend_foods = my_foods[:]

my_foods.append(‘cannoli‘)
friend_foods.append(‘ice cream‘)

print("my favorite food are:")
print(my_foods)

print("my friend favorite food are:")
print(friend_foods)

print()
#用赋值的方式得到的效果只是两次都一样
my_foods = [‘pizza‘,‘falafel‘,‘carrot cake‘]
friend_foods = my_foods
#python只是把两个变量关联起来了，而不是向上面一样做成一个副本
my_foods.append(‘cannoli‘)
friend_foods.append(‘ice cream‘)

print("my favorite food are:")
print(my_foods)

print("my friend favorite food are:")
print(friend_foods)

#4-10 切片
fruits = [‘banana‘,‘apple‘,‘pear‘,‘tomato‘,‘watermelon‘]
print("The first there items in the list are:")
print(fruits[:3])
print(fruits[1:4])
print(fruits[-3:])

#4-11 披萨
my_pizzas = [‘durian pizza‘,‘apple pizza‘,‘banana pizza‘]
friend_pizzas = my_pizzas[:]

my_pizzas.append("pear pizza")
friend_pizzas.append("tomato pizza")

print("My favorite pizzas are:")
for pizza in my_pizzas:
	print(pizza,end=",")
print()
print("My friend‘s favorite pizzas are:")
for pizza in friend_pizzas:
	print(pizza,end=",")
print()

#4.5.1 定义元组
dimensions = (200,50)
print(dimensions[0])
print(dimensions[1])
#修改元组的操作事被禁止的，python指出不能给元组的元素赋值
#dimensions[0] = 250

#4.5.2 遍历元组中的所有值
dimensions = (200,50)
for dimension in dimensions:
	print(dimension)

#4.5.3 修改元组变量
dimensions = (200,50)
print("Original dimensions:",end=" ")
for dimension in dimensions:
	print(dimension,end = " ")
print()

dimensions = (400,100)
print("modified dimensions:",end=" ")
for dimension in dimensions:
	print(dimension,end=" ")
#不能单独改变元组中的元素，但是可以使用元组的变量重新定义

#4-13 自助餐
print()
foods = (‘milk‘,‘bread‘,‘egg‘,‘rice‘,‘apple‘)
for food in foods:
	print(food,end=" ")

#foods[0] = ‘banana‘
print()
foods = (‘milk‘,‘bread‘,‘meat‘,‘rice‘,‘banana‘)
for food in foods:
	print(food,end=" ")

Python小结

在本章中，学习了：如何高效的处理列表中的元素；如何使用for循环遍历列表，python如何根据缩进来确定程序的结构以及如何避免一些常见的缩进错误；如何创建简单的数字列表，以及可对数字列表执行的一些操作；如何通过切片来使用列表的一部分和复制列表。还学习了元组（它对不应变化的值提供了一定程度的保护），以及在代码变的越来越复杂时如何设置格式，使其易于阅读。