From 9c2caad067eccbbfb90796b91022f4d64e815280 Mon Sep 17 00:00:00 2001
From: Zero <39959756+Gonglja@users.noreply.github.com>
Date: Mon, 30 Jan 2023 16:05:57 +0800
Subject: [PATCH] Add queue array impl in C (#300)

* feat(codes/c): Add array_queue.c initialization

* feat(codes/c): Add array_queue.c impl

* style(codes/c): Update array_queue.c code style

* style(codes/c): Update array_queue.c code style
---
 .../c/chapter_stack_and_queue/CMakeLists.txt  |   3 +-
 codes/c/chapter_stack_and_queue/array_queue.c | 130 ++++++++++++++++++
 2 files changed, 132 insertions(+), 1 deletion(-)
 create mode 100644 codes/c/chapter_stack_and_queue/array_queue.c

diff --git a/codes/c/chapter_stack_and_queue/CMakeLists.txt b/codes/c/chapter_stack_and_queue/CMakeLists.txt
index 5c2be36b6..8b2153ca5 100644
--- a/codes/c/chapter_stack_and_queue/CMakeLists.txt
+++ b/codes/c/chapter_stack_and_queue/CMakeLists.txt
@@ -1,2 +1,3 @@
 add_executable(array_stack array_stack.c)
-add_executable(linkedlist_stack linkedlist_stack.c)
\ No newline at end of file
+add_executable(linkedlist_stack linkedlist_stack.c)
+add_executable(array_queue array_queue.c)
\ No newline at end of file
diff --git a/codes/c/chapter_stack_and_queue/array_queue.c b/codes/c/chapter_stack_and_queue/array_queue.c
new file mode 100644
index 000000000..7783e49b8
--- /dev/null
+++ b/codes/c/chapter_stack_and_queue/array_queue.c
@@ -0,0 +1,130 @@
+/**
+ * File: array_queue.c
+ * Created Time: 2023-01-28
+ * Author: Zero (glj0@outlook.com)
+ */
+
+#include "../include/include.h"
+
+/* 基于环形数组形成的队列 */
+struct ArrayQueue {
+    int *nums;    // 用于存储队列元素的数组
+    int cap;      // 队列容量
+    int front;    // 头指针，指向队首
+    int rear;     // 尾指针，指向队尾 + 1
+};
+
+typedef struct ArrayQueue ArrayQueue;
+
+/* 构造函数 */
+ArrayQueue *newArrayQueue(int capacity) {
+    ArrayQueue *queue = (ArrayQueue *) malloc(sizeof(ArrayQueue));
+    // 初始化数组
+    queue->cap = capacity;
+    queue->nums = (int *) malloc(sizeof(int) * queue->cap);
+    queue->front = 0;
+    queue->rear = 0;
+    return queue;
+}
+
+/* 析构函数 */
+void delArrayQueue(ArrayQueue *queue) {
+    free(queue->nums);
+    queue->cap = 0;
+}
+
+/* 获取队列的容量 */
+int capacity(ArrayQueue *queue) {
+    return queue->cap;
+}
+
+/* 获取队列的长度 */
+int size(ArrayQueue *queue) {
+    // 由于将数组看作环形队列，可能 rear < front，因此需要取余数
+    return (capacity(queue) + queue->rear - queue->front) % capacity(queue);
+}
+
+/* 判断队列是否为空 */
+bool empty(ArrayQueue *queue) {
+    return queue->rear - queue->front == 0;
+}
+
+/* 访问队首元素 */
+int peek(ArrayQueue *queue) {
+  assert(size(queue) != 0);
+  return queue->nums[queue->front];
+}
+
+/* 入队 */
+void offer(ArrayQueue *queue, int num) {
+    if (size(queue) == capacity(queue)) {
+        printf("队列已满\r\n");
+        return;
+    }
+    queue->nums[queue->rear] = num;
+    queue->rear = (queue->rear + 1) % capacity(queue);
+}
+
+/*  出队 */
+void poll(ArrayQueue *queue) {
+    int num = peek(queue);
+    queue->front = (queue->front + 1) % capacity(queue);
+}
+
+/* 打印基于环形数组形成的队列 */
+void printArrayQueue(ArrayQueue *queue) {
+    int siz = size(queue);
+    int cap = capacity(queue);
+    int arr[siz];
+    // 拷贝
+    for (int i = 0, j = queue->front; i < siz; i++, j++) {
+        arr[i] = queue->nums[j % cap];
+    }
+    printArray(arr, siz);
+}
+
+
+/* Driver Code */
+int main() {
+    /* 初始化队列 */
+    int capacity = 10;
+    ArrayQueue *queue = newArrayQueue(capacity);
+
+    /* 元素入队 */
+    offer(queue, 1);
+    offer(queue, 3);
+    offer(queue, 2);
+    offer(queue, 5);
+    offer(queue, 4);
+    printf("队列 queue = ");
+    printArrayQueue(queue);
+
+    /* 访问队首元素 */
+    int peekNum = peek(queue);
+    printf("队首元素 peek = %d\r\n", peekNum);
+
+    /* 元素出队 */
+    poll(queue);
+    printf("出队元素 poll = %d，出队后 queue = ", peekNum);
+    printArrayQueue(queue);
+
+    /* 获取队列的长度 */
+    int queueSize = size(queue);
+    printf("队列长度 size = %d\r\n", queueSize);
+
+    /* 判断队列是否为空 */
+    bool isEmpty = empty(queue);
+    printf("队列是否为空 = %s\r\n", isEmpty ? "true" : "false");
+
+    /* 测试环形数组 */
+    for (int i = 0; i < 10; i++) {
+        offer(queue, i);
+        poll(queue);
+        printf("第 %d 轮入队 + 出队后 queue = ", i);
+        printArrayQueue(queue);
+    }
+
+    // 释放内存
+    delArrayQueue(queue);
+    return 0;
+}
\ No newline at end of file