feat(codes/c): Add array_deque.c (krahets#412)

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

* Update array_deque.c

---------

Co-authored-by: Yudong Jin <[email protected]>

codes/c/chapter_stack_and_queue/CMakeLists.txt

@@ -2,3 +2,4 @@ add_executable(array_stack array_stack.c)
 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)

codes/c/chapter_stack_and_queue/array_deque.c

@@ -0,0 +1,171 @@
+/**
+ * File: array_deque.c
+ * Created Time: 2023-03-13
+ * Author: Gonglja ([email protected])
+ */
+
+#include "../include/include.h"
+
+/* 基于环形数组形成的双向队列 */
+struct ArrayDeque {
+    int *nums;       // 用于存储队列元素的数组
+    int front;       // 队首指针，指向队首元素
+    int queSize;     // 尾指针，指向队尾 + 1
+    int queCapacity; // 队列容量
+};
+
+typedef struct ArrayDeque ArrayDeque;
+
+/* 构造方法 */
+ArrayDeque *newArrayDeque(int capacity) {
+    ArrayDeque *deque = (ArrayDeque *) malloc(sizeof(ArrayDeque));
+    // 初始化数组
+    deque->queCapacity = capacity;
+    deque->nums = (int *) malloc(sizeof(int) * deque->queCapacity);
+    deque->front = deque->queSize = 0;
+    return deque;
+}
+
+/* 析构方法 */
+void delArrayDeque(ArrayDeque *deque) {
+    free(deque->nums);
+    deque->queCapacity = 0;
+}
+
+/* 获取双向队列的容量 */
+int capacity(ArrayDeque *deque) {
+    return deque->queCapacity;
+}
+
+/* 获取双向队列的长度 */
+int size(ArrayDeque *deque) {
+    return deque->queSize;
+}
+
+/* 判断双向队列是否为空 */
+bool empty(ArrayDeque *deque) {
+    return deque->queSize == 0;
+}
+
+int dequeIndex(ArrayDeque *deque, int i) {
+    // 通过取余操作实现数组首尾相连
+    // 当 i 越过数组尾部时，回到头部
+    // 当 i 越过数组头部后，回到尾部
+    return ((i + capacity(deque)) % capacity(deque));
+}
+
+/* 队首入队 */
+void pushFirst(ArrayDeque *deque, int num) {
+    if (deque->queSize == capacity(deque)) {
+        printf("双向队列已满\r\n");
+        return;
+    }
+    // 队首指针向左移动一位
+    // 通过取余操作，实现 front 越过数组头部回到尾部
+    deque->front = dequeIndex(deque, deque->front - 1);
+    // 将 num 添加到队首
+    deque->nums[deque->front] = num;
+    deque->queSize++;
+}
+
+/* 队尾入队 */
+void pushLast(ArrayDeque *deque, int num) {
+    if (deque->queSize == capacity(deque)) {
+        printf("双向队列已满\r\n");
+        return;
+    }
+    // 计算尾指针，指向队尾索引 + 1
+    int rear = dequeIndex(deque, deque->front + deque->queSize);
+    // 将 num 添加至队尾
+    deque->nums[rear] = num;
+    deque->queSize++;
+}
+
+/* 访问队首元素 */
+int peekFirst(ArrayDeque *deque) {
+    // 访问异常：双向队列为空
+    assert(empty(deque) == 0);
+    return deque->nums[deque->front];        
+}
+
+/* 访问队尾元素 */
+int peekLast(ArrayDeque *deque) {
+    // 访问异常：双向队列为空
+    assert(empty(deque) == 0);
+    int last = dequeIndex(deque, deque->front + deque->queSize - 1);
+    return deque->nums[last];     
+}
+
+/* 队首出队 */
+int pollFirst(ArrayDeque *deque) {
+    int num = peekFirst(deque);
+    // 队首指针向后移动一位
+    deque->front = dequeIndex(deque, deque->front + 1);
+    deque->queSize--;
+    return num;
+}
+
+/* 队尾出队 */
+int pollLast(ArrayDeque *deque) {
+    int num = peekLast(deque);
+    deque->queSize--;
+    return num;
+}
+
+/* 打印基于环形数组形成的队列 */
+void printArrayDeque(ArrayDeque *deque) {
+    int arr[deque->queSize];
+    // 拷贝
+    for (int i = 0, j = deque->front; i < deque->queSize; i++, j++) {
+        arr[i] = deque->nums[j % deque->queCapacity];
+    }
+    printArray(arr, deque->queSize);
+}
+
+
+/* Driver Code */
+int main() {
+    /* 初始化队列 */
+    int capacity = 10;
+    ArrayDeque *deque = newArrayDeque(capacity);
+    pushLast(deque, 3);
+    pushLast(deque, 2);
+    pushLast(deque, 5);
+    printf("双向队列 deque = ");
+    printArrayDeque(deque);
+
+    /* 访问元素 */
+    int peekFirstNum = peekFirst(deque);
+    printf("队首元素 peekFirst = %d\r\n", peekFirstNum);
+    int peekLastNum = peekLast(deque);
+    printf("队尾元素 peekLast = %d\r\n", peekLastNum);
+
+    /* 元素入队 */
+    pushLast(deque, 4);
+    printf("元素 4 队尾入队后 deque = ");
+    printArrayDeque(deque);
+    pushFirst(deque, 1);
+    printf("元素 1 队首入队后 deque = ");
+    printArrayDeque(deque);
+
+    /* 元素出队 */
+    int pollLastNum = pollLast(deque);
+    printf("队尾出队元素 = %d，队尾出队后 deque= ", pollLastNum);
+    printArrayDeque(deque);
+    int pollFirstNum = pollFirst(deque);
+    printf("队首出队元素 = %d，队首出队后 deque= ", pollFirstNum);
+    printArrayDeque(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("队列是否为空 = %s\r\n", isEmpty ? "true" : "false");
+
+    // 释放内存
+    delArrayDeque(deque);
+
+    return 0;
+}