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update stack and queue.

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This commit is contained in:
Yudong Jin
2022-11-30 03:46:53 +08:00
parent 8669e06414
commit acfdc713ba
13 changed files with 321 additions and 124 deletions
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178
docs/chapter_stack_and_queue/queue.md
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@@ -44,29 +44,44 @@ comments: true
queue.offer(2);
queue.offer(5);
queue.offer(4);
System.out.println("队列 queue = " + queue);
/* 访问队首元素 */
int peek = queue.peek();
System.out.println("队首元素 peek = " + peek);
/* 元素出队 */
int poll = queue.poll();
System.out.println("出队元素 poll = " + poll + "，出队后 queue = " + queue);
/* 获取队列的长度 */
int size = queue.size();
System.out.println("队列长度 size = " + size);
/* 判断队列是否为空 */
boolean isEmpty = queue.isEmpty();
System.out.println("队列是否为空 = " + isEmpty);
```
=== "C++"
```cpp title="queue.cpp"
/* 初始化队列 */
queue<int> queue;
/* 元素入队 */
queue.push(1);
queue.push(3);
queue.push(2);
queue.push(5);
queue.push(4);
/* 访问队首元素 */
int front = queue.front();
/* 元素出队 */
queue.pop();
/* 获取队列的长度 */
int size = queue.size();
/* 判断队列是否为空 */
bool empty = queue.empty();
```
=== "Python"
@@ -88,33 +103,49 @@ comments: true
```java title="linkedlist_queue.java"
/* 基于链表实现的队列 */
class LinkedListQueue {
LinkedList<Integer> list;
private ListNode front, rear; // 头结点 front ，尾结点 rear
private int queSize = 0;
public LinkedListQueue() {
// 初始化链表
list = new LinkedList<>();
front = null;
rear = null;
}
/* 获取队列的长度 */
public int size() {
return list.size();
return queSize;
}
/* 判断队列是否为空 */
public boolean isEmpty() {
return list.size() == 0;
return size() == 0;
}
/* 入队 */
public void offer(int num) {
// 尾结点后添加 num
list.addLast(num);
ListNode node = new ListNode(num);
// 如果队列为空，则令头、尾结点都指向该结点
if (front == null) {
front = node;
rear = node;
// 如果队列不为空，则将该结点添加到尾结点后
} else {
rear.next = node;
rear = node;
}
queSize++;
}
/* 出队 */
public int poll() {
int num = peek();
// 删除头结点
return list.removeFirst();
front = front.next;
queSize--;
return num;
}
/* 访问队首元素 */
public int peek() {
return list.getFirst();
if (size() == 0)
throw new IndexOutOfBoundsException();
return front.val;
}
}
```
@@ -122,7 +153,57 @@ comments: true
=== "C++"
```cpp title="linkedlist_queue.cpp"
/* 基于链表实现的队列 */
class LinkedListQueue {
private:
ListNode *front, *rear; // 头结点 front ，尾结点 rear
int queSize;
public:
LinkedListQueue() {
front = nullptr;
rear = nullptr;
queSize = 0;
}
/* 获取队列的长度 */
int size() {
return queSize;
}
/* 判断队列是否为空 */
bool empty() {
return queSize == 0;
}
/* 入队 */
void offer(int num) {
// 尾结点后添加 num
ListNode* node = new ListNode(num);
// 如果队列为空，则令头、尾结点都指向该结点
if (front == nullptr) {
front = node;
rear = node;
}
// 如果队列不为空，则将该结点添加到尾结点后
else {
rear->next = node;
rear = node;
}
queSize++;
}
/* 出队 */
int poll() {
int num = peek();
// 删除头结点
front = front->next;
queSize--;
return num;
}
/* 访问队首元素 */
int peek() {
if (size() == 0)
throw out_of_range("队列为空");
return front->val;
}
};
```
=== "Python"
@@ -196,13 +277,80 @@ comments: true
throw new EmptyStackException();
return nums[front];
}
/* 访问指定索引元素 */
int get(int index) {
if (index >= size())
throw new IndexOutOfBoundsException();
return nums[(front + index) % capacity()];
}
}
```
=== "C++"
```cpp title="array_queue.cpp"
/* 基于环形数组实现的队列 */
class ArrayQueue {
private:
int *nums; // 用于存储队列元素的数组
int cap; // 队列容量
int front = 0; // 头指针，指向队首
int rear = 0; // 尾指针，指向队尾 + 1
public:
ArrayQueue(int capacity) {
// 初始化数组
cap = capacity;
nums = new int[capacity];
}
/* 获取队列的容量 */
int capacity() {
return cap;
}
/* 获取队列的长度 */
int size() {
// 由于将数组看作为环形，可能 rear < front ，因此需要取余数
return (capacity() + rear - front) % capacity();
}
/* 判断队列是否为空 */
bool empty() {
return rear - front == 0;
}
/* 入队 */
void offer(int num) {
if (size() == capacity()) {
cout << "队列已满" << endl;
return;
}
// 尾结点后添加 num
nums[rear] = num;
// 尾指针向后移动一位，越过尾部后返回到数组头部
rear = (rear + 1) % capacity();
}
/* 出队 */
int poll() {
// 删除头结点
if (empty())
throw out_of_range("队列为空");
int num = nums[front];
// 队头指针向后移动，越过尾部后返回到数组头部
front = (front + 1) % capacity();
return num;
}
/* 访问队首元素 */
int peek() {
// 删除头结点
if (empty())
throw out_of_range("队列为空");
return nums[front];
}
/* 访问指定位置元素 */
int get(int index) {
if (index >= size())
throw out_of_range("索引越界");
return nums[(front + index) % capacity()]
}
};
```
=== "Python"