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Update stack and queue.

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This commit is contained in:
Yudong Jin
2022-11-30 02:27:26 +08:00
parent 53cc651af2
commit 8669e06414
24 changed files with 705 additions and 186 deletions
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25
docs/chapter_stack_and_queue/deque.md
View File

@@ -38,35 +38,34 @@ comments: true
```java title="deque.java"
/* 初始化双向队列 */
Deque<Integer> deque = new LinkedList<>();
/* 元素入队 */
deque.offerLast(2);
deque.offerLast(5);
deque.offerLast(4);
deque.offerFirst(3);
deque.offerFirst(1);
System.out.println("队列 deque = " + deque);
System.out.println("双向队列 deque = " + deque);
/* 访问队首元素 */
int peekFirst = deque.peekFirst();
System.out.println("队首元素 peekFirst = " + peekFirst);
int peekLast = deque.peekLast();
System.out.println("队尾元素 peekLast = " + peekLast);
/* 元素出队 */
int pollFirst = deque.pollFirst();
System.out.println("队首出队元素 pollFirst = " + pollFirst +
"，队首出队后 deque = " + deque);
System.out.println("队首出队元素 pollFirst = " + pollFirst + "，队首出队后 deque = " + deque);
int pollLast = deque.pollLast();
System.out.println("队尾出队元素 pollLast = " + pollLast +
"，队尾出队后 deque = " + deque);
/* 获取队列的长度 */
System.out.println("队尾出队元素 pollLast = " + pollLast + "，队尾出队后 deque = " + deque);
/* 获取双向队列的长度 */
int size = deque.size();
System.out.println("队列长度 size = " + size);
/* 判断队列是否为空 */
System.out.println("双向队列长度 size = " + size);
/* 判断双向队列是否为空 */
boolean isEmpty = deque.isEmpty();
System.out.println("双向队列是否为空 = " + isEmpty);
```
=== "C++"

8
docs/chapter_stack_and_queue/queue.md
View File

@@ -60,6 +60,7 @@ comments: true
/* 判断队列是否为空 */
boolean isEmpty = queue.isEmpty();
System.out.println("队列是否为空 = " + isEmpty);
```
=== "C++"
@@ -145,10 +146,9 @@ comments: true
```java title="array_queue.java"
/* 基于环形数组实现的队列 */
class ArrayQueue {
int[] nums; // 用于存储队列元素的数组
int size = 0; // 队列长度（即元素个数）
int front = 0; // 头指针，指向队首
int rear = 0; // 尾指针，指向队尾 + 1
private int[] nums; // 用于存储队列元素的数组
private int front = 0; // 头指针，指向队首
private int rear = 0; // 尾指针，指向队尾 + 1
public ArrayQueue(int capacity) {
// 初始化数组

258
docs/chapter_stack_and_queue/stack.md
View File

@@ -36,22 +36,23 @@ comments: true
```java title="stack.java"
/* 初始化栈 */
Stack<Integer> stack = new Stack<>();
// 在 Java 中，推荐将 LinkedList 当作栈来使用
LinkedList<Integer> stack = new LinkedList<>();
/* 元素入栈 */
stack.push(1);
stack.push(3);
stack.push(2);
stack.push(5);
stack.push(4);
stack.addLast(1);
stack.addLast(3);
stack.addLast(2);
stack.addLast(5);
stack.addLast(4);
System.out.println("栈 stack = " + stack);
/* 访问栈顶元素 */
int peek = stack.peek();
int peek = stack.peekLast();
System.out.println("栈顶元素 peek = " + peek);
/* 元素出栈 */
int pop = stack.pop();
int pop = stack.removeLast();
System.out.println("出栈元素 pop = " + pop + "，出栈后 stack = " + stack);
/* 获取栈的长度 */
@@ -60,18 +61,73 @@ comments: true
/* 判断是否为空 */
boolean isEmpty = stack.isEmpty();
System.out.println("栈是否为空 = " + isEmpty);
```
=== "C++"
```cpp title="stack.cpp"
/* 初始化栈 */
stack<int> stack;
/* 元素入栈 */
stack.push(1);
stack.push(3);
stack.push(2);
stack.push(5);
stack.push(4);
cout << "栈 stack = ";
PrintUtil::printStack(stack);
/* 访问栈顶元素 */
int top = stack.top();
cout << "栈顶元素 top = " << top << endl;
/* 元素出栈 */
stack.pop();
cout << "出栈元素 pop = " << top << "，出栈后 stack = ";
PrintUtil::printStack(stack);
/* 获取栈的长度 */
int size = stack.size();
cout << "栈的长度 size = " << size << endl;
/* 判断是否为空 */
bool empty = stack.empty();
cout << "栈是否为空 = " << empty << endl;
```
=== "Python"
```python title="stack.py"
""" 初始化栈 """
# Python 没有内置的栈类，可以把 list 当作栈来使用
stack = []
""" 元素入栈 """
stack.append(1)
stack.append(3)
stack.append(2)
stack.append(5)
stack.append(4)
print("栈 stack =", stack)
""" 访问栈顶元素 """
peek = stack[-1]
print("栈顶元素 peek =", peek)
""" 元素出栈 """
pop = stack.pop()
print("出栈元素 pop =", pop)
print("出栈后 stack =", stack)
""" 获取栈的长度 """
size = len(stack)
print("栈的长度 size =", size)
""" 判断是否为空 """
is_empty = len(stack) == 0
print("栈是否为空 =", is_empty)
```
## 栈的实现
@@ -91,14 +147,15 @@ comments: true
```java title="linkedlist_stack.java"
/* 基于链表实现的栈 */
class LinkedListStack {
LinkedList<Integer> list;
private ListNode stackPeek; // 将头结点作为栈顶
private int stackSize = 0; // 栈的长度
public LinkedListStack() {
// 初始化链表
list = new LinkedList<>();
stackPeek = null;
}
/* 获取栈的长度 */
public int size() {
return list.size();
return stackSize;
}
/* 判断栈是否为空 */
public boolean isEmpty() {
@@ -106,15 +163,25 @@ comments: true
}
/* 入栈 */
public void push(int num) {
list.addLast(num);
ListNode node = new ListNode(num);
node.next = stackPeek;
stackPeek = node;
stackSize++;
}
/* 出栈 */
public int pop() {
return list.removeLast();
if (size() == 0)
throw new IndexOutOfBoundsException();
int num = peek();
stackPeek = stackPeek.next;
stackSize--;
return num;
}
/* 访问栈顶元素 */
public int peek() {
return list.getLast();
if (size() == 0)
throw new IndexOutOfBoundsException();
return stackPeek.val;
}
}
```
@@ -122,13 +189,88 @@ comments: true
=== "C++"
```cpp title="linkedlist_stack.cpp"
/* 基于链表实现的栈 */
class LinkedListStack {
private:
ListNode* stackTop; // 将头结点作为栈顶
int stackSize; // 栈的长度
public:
LinkedListStack() {
stackTop = nullptr;
stackSize = 0;
}
/* 获取栈的长度 */
int size() {
return stackSize;
}
/* 判断栈是否为空 */
bool empty() {
return size() == 0;
}
/* 入栈 */
void push(int num) {
ListNode* node = new ListNode(num);
node->next = stackTop;
stackTop = node;
stackSize++;
}
/* 出栈 */
int pop() {
if (size() == 0)
throw out_of_range("栈为空");
int num = stackTop->val;
stackTop = stackTop->next;
stackSize--;
return num;
}
/* 访问栈顶元素 */
int top() {
if (size() == 0)
throw out_of_range("栈为空");
return stackTop->val;
}
};
```
=== "Python"
```python title="linkedlist_stack.py"
""" 基于链表实现的栈 """
class LinkedListStack:
def __init__(self):
self.__peek = None
self.__size = 0
""" 获取栈的长度 """
def size(self):
return self.__size
""" 判断栈是否为空 """
def is_empty(self):
return not self.__peek
""" 入栈 """
def push(self, val):
node = ListNode(val)
node.next = self.__peek
self.__peek = node
self.__size += 1
""" 出栈 """
def pop(self):
# 判空处理
if not self.__peek: return None
pop = self.__peek.val
self.__peek = self.__peek.next
self.__size -= 1
return pop
""" 访问栈顶元素 """
def peek(self):
# 判空处理
if not self.__peek: return None
return self.__peek.val
```
### 基于数组的实现
@@ -142,14 +284,14 @@ comments: true
```java title="array_stack.java"
/* 基于数组实现的栈 */
class ArrayStack {
List<Integer> list;
private ArrayList<Integer> stack;
public ArrayStack() {
// 初始化列表（动态数组）
list = new ArrayList<>();
stack = new ArrayList<>();
}
/* 获取栈的长度 */
public int size() {
return list.size();
return stack.size();
}
/* 判断栈是否为空 */
public boolean isEmpty() {
@@ -157,19 +299,19 @@ comments: true
}
/* 入栈 */
public void push(int num) {
list.add(num);
stack.add(num);
}
/* 出栈 */
public int pop() {
return list.remove(size() - 1);
return stack.remove(size() - 1);
}
/* 访问栈顶元素 */
public int peek() {
return list.get(size() - 1);
return stack.get(size() - 1);
}
/* 访问索引 index 处元素 */
public int get(int index) {
return list.get(index);
return stack.get(index);
}
}
```
@@ -177,13 +319,72 @@ comments: true
=== "C++"
```cpp title="array_stack.cpp"
/* 基于数组实现的栈 */
class ArrayStack {
private:
vector<int> stack;
public:
/* 获取栈的长度 */
int size() {
return stack.size();
}
/* 判断栈是否为空 */
bool empty() {
return stack.empty();
}
/* 入栈 */
void push(int num) {
stack.push_back(num);
}
/* 出栈 */
int pop() {
int oldTop = stack.back();
stack.pop_back();
return oldTop;
}
/* 访问栈顶元素 */
int top() {
return stack.back();
}
/* 访问索引 index 处元素 */
int get(int index) {
return stack[index];
}
};
```
=== "Python"
```python title="array_stack.py"
""" 基于数组实现的栈 """
class ArrayStack:
def __init__(self):
self.__stack = []
""" 获取栈的长度 """
def size(self):
return len(self.__stack)
""" 判断栈是否为空 """
def is_empty(self):
return self.__stack == []
""" 入栈 """
def push(self, item):
self.__stack.append(item)
""" 出栈 """
def pop(self):
return self.__stack.pop()
""" 访问栈顶元素 """
def peek(self):
return self.__stack[-1]
""" 访问索引 index 处元素 """
def get(self, index):
return self.__stack[index]
```
!!! tip
@@ -193,5 +394,4 @@ comments: true
## 栈典型应用
- **浏览器中的后退与前进、软件中的撤销与反撤销。** 每当我们打开新的网页，浏览器就讲上一个网页执行入栈，这样我们就可以通过「后退」操作来回到上一页面，后退操作实际上是在执行出栈。如果要同时支持后退和前进，那么则需要两个栈来配合实现。
- **程序内存管理。** 每当调用函数时，系统就会在栈顶添加一个栈帧，用来记录函数的上下文信息。在递归函数中，向下递推会不断执行入栈，向上回溯阶段时出栈。