feat(codes/c): Add linkedlist_deque.c (krahets#422)

* feat(codes/c): Add linkedlist_deque.c

* feat(codes/c): Update linkedlist_deque.c function comment.

* feat(codes/c): Update linkedlist_deque.c driver code.

codes/c/chapter_stack_and_queue/CMakeLists.txt

@@ -3,3 +3,4 @@ add_executable(linkedlist_stack linkedlist_stack.c)
 add_executable(array_queue array_queue.c)
 add_executable(linkedlist_queue linkedlist_queue.c)
 add_executable(array_deque array_deque.c)
+add_executable(linkedlist_deque linkedlist_deque.c)

codes/c/chapter_stack_and_queue/linkedlist_deque.c

@@ -0,0 +1,214 @@
+/**
+ * File: linkedlist_deque.c
+ * Created Time: 2023-03-13
+ * Author: Gonglja ([email protected])
+ */
+
+#include "../include/include.h"
+
+/* 双向链表结点 */
+struct DoublyListNode {
+    int val;                     // 结点值
+    struct DoublyListNode *next; // 后继结点
+    struct DoublyListNode *prev; // 前驱结点
+};
+
+typedef struct DoublyListNode DoublyListNode;
+
+/* 双向链表结点构造方法 */
+DoublyListNode *newDoublyListNode(int num) {
+    DoublyListNode* new = (DoublyListNode *) malloc(sizeof(DoublyListNode));
+    new->val = num;
+    new->next = NULL;
+    new->prev = NULL;
+    return new;
+}
+
+/* 双向链表结点析构方法 */
+void delDoublyListNode(DoublyListNode *node) {
+    free(node);
+}
+
+/* 基于双向链表实现的双向队列 */
+struct LinkedListDeque {
+    DoublyListNode *front, *rear; // 头结点 front ，尾结点 rear
+    int queSize;                  // 双向队列的长度
+};
+
+typedef struct LinkedListDeque LinkedListDeque;
+
+/* 构造方法 */
+LinkedListDeque *newLinkedListDeque() {
+    LinkedListDeque *deque = (LinkedListDeque *) malloc(sizeof(LinkedListDeque));
+    deque->front = NULL;
+    deque->rear = NULL;
+    deque->queSize = 0;
+}
+
+/* 析构方法 */
+void delLinkedListdeque(LinkedListDeque *deque) {
+    // 释放所有结点
+    for (int i=0; i<deque->queSize && deque->front != NULL; i++) {
+        DoublyListNode *tmp = deque->front;
+        deque->front = deque->front->next;
+        free(tmp);
+    }
+    // 释放 deque 结构体
+    free(deque);
+}
+
+/* 获取队列的长度 */
+int size(LinkedListDeque *deque) {
+    return deque->queSize;
+}
+
+/* 判断队列是否为空 */
+bool empty(LinkedListDeque *deque) {
+    return (size(deque) == 0);
+}
+
+/* 入队 */
+void push(LinkedListDeque *deque, int num, bool isFront) {
+    DoublyListNode *node = newDoublyListNode(num);
+    // 若链表为空，则令 front, rear 都指向node
+    if (empty(deque)) {
+        deque->front = deque->rear = node;
+    }
+    // 队首入队操作
+    else if (isFront){
+        // 将 node 添加至链表头部
+        deque->front->prev = node;
+        node->next = deque->front;
+        deque->front = node;// 更新头结点
+    }
+    // 对尾入队操作
+    else {
+        // 将 node 添加至链表尾部
+        deque->rear->next = node;
+        node->prev = deque->rear;
+        deque->rear = node;
+    }
+    deque->queSize++; // 更新队列长度
+}
+
+/* 队首入队 */
+void pushFirst(LinkedListDeque *deque, int num) {
+    push(deque, num, true);
+}
+
+/* 队尾入队 */
+void pushLast(LinkedListDeque *deque, int num) {
+    push(deque, num, false);
+}
+
+/* 访问队首元素 */
+int peekFirst(LinkedListDeque *deque) {
+    assert(size(deque) && deque->front);
+    return deque->front->val;
+}
+
+/* 访问队尾元素 */
+int peekLast(LinkedListDeque *deque) {
+    assert(size(deque) && deque->rear);
+    return deque->rear->val;
+}
+
+/* 出队 */
+int pop(LinkedListDeque *deque, bool isFront) {
+    if (empty(deque))
+        return -1;
+    int val;
+    // 队首出队操作
+    if(isFront) {
+        val = peekFirst(deque); // 暂存头结点值
+        DoublyListNode *fNext = deque->front->next;
+        if (fNext) {
+            fNext->prev = NULL;
+            deque->front->next = NULL;
+            delDoublyListNode(deque->front);
+        }
+        deque->front = fNext; // 更新头结点
+    }
+    // 队尾出队操作
+    else {
+        val = peekLast(deque); // 暂存尾结点值
+        DoublyListNode *rPrev = deque->rear->prev;
+        if (rPrev) {
+            rPrev->next = NULL;
+            deque->rear->prev = NULL;
+            delDoublyListNode(deque->rear);
+        }
+        deque->rear = rPrev; // 更新尾结点
+    }
+    deque->queSize--;      // 更新队列长度
+    return val;
+}
+
+/* 队首出队 */
+int popFirst(LinkedListDeque *deque) {
+    return pop(deque, true);
+}
+
+/* 队尾出队 */
+int popLast(LinkedListDeque *deque) {
+    return pop(deque, false);
+}
+
+/* 打印队列 */
+void printLinkedListDeque(LinkedListDeque *deque) {
+    int arr[deque->queSize];
+    // 拷贝链表中的数据到数组
+    int i;
+    DoublyListNode *node;
+    for (i=0, node = deque->front; i < deque->queSize; i++){
+      arr[i] = node->val;
+      node = node->next;
+    }
+    printArray(arr, deque->queSize);
+}
+
+/* Driver Code */
+int main() {
+    /* 初始化双向队列 */
+    LinkedListDeque *deque = newLinkedListDeque();
+    pushLast(deque, 3);
+    pushLast(deque, 2);
+    pushLast(deque, 5);
+    printf("双向队列 deque = ");
+    printLinkedListDeque(deque);
+
+    /* 访问元素 */
+    int peekFirstNum = peekFirst(deque);
+    printf("队首元素 peekFirst = %d\r\n", peekFirstNum);
+    int peekLastNum = peekLast(deque);
+    printf("队首元素 peekLast = %d\r\n", peekLastNum);
+
+    /* 元素入队 */
+    pushLast(deque, 4);
+    printf("元素 4 队尾入队后 deque =");
+    printLinkedListDeque(deque);
+    pushFirst(deque, 1);
+    printf("元素 1 队首入队后 deque =");
+    printLinkedListDeque(deque);
+
+    /* 元素出队 */
+    int popLastNum = popLast(deque);
+    printf("队尾出队元素 popLast = %d，队尾出队后 deque = ", popLastNum);
+    printLinkedListDeque(deque);
+    int popFirstNum = popFirst(deque);
+    printf("队首出队元素 popFirst = %d，队首出队后 deque = ", popFirstNum);
+    printLinkedListDeque(deque);
+
+    /* 获取队列的长度 */
+    int dequeSize = size(deque);
+    printf("双向队列长度 size = %d\r\n", dequeSize);
+
+    /* 判断队列是否为空 */
+    bool isEmpty = empty(deque);
+    printf("双向队列是否为空 = %s\r\n", isEmpty ? "true" : "false");
+
+    /* 释放内存 */
+    delLinkedListdeque(deque);
+    return 0;
+}
+