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160 lines
4.3 KiB
160 lines
4.3 KiB
/**
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* File: array_deque.c
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* Created Time: 2023-03-13
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* Author: Gonglja (glj0@outlook.com)
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*/
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#include "../utils/common.h"
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/* 基于环形数组实现的双向队列 */
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typedef struct {
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int *nums; // 用于存储队列元素的数组
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int front; // 队首指针，指向队首元素
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int queSize; // 尾指针，指向队尾 + 1
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int queCapacity; // 队列容量
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} ArrayDeque;
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/* 构造函数 */
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ArrayDeque *newArrayDeque(int capacity) {
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ArrayDeque *deque = (ArrayDeque *)malloc(sizeof(ArrayDeque));
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// 初始化数组
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deque->queCapacity = capacity;
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deque->nums = (int *)malloc(sizeof(int) * deque->queCapacity);
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deque->front = deque->queSize = 0;
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return deque;
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}
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/* 析构函数 */
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void delArrayDeque(ArrayDeque *deque) {
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free(deque->nums);
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free(deque);
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}
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/* 获取双向队列的容量 */
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int capacity(ArrayDeque *deque) {
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return deque->queCapacity;
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}
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/* 获取双向队列的长度 */
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int size(ArrayDeque *deque) {
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return deque->queSize;
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}
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/* 判断双向队列是否为空 */
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bool empty(ArrayDeque *deque) {
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return deque->queSize == 0;
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}
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/* 计算环形数组索引 */
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int dequeIndex(ArrayDeque *deque, int i) {
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// 通过取余操作实现数组首尾相连
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// 当 i 越过数组尾部时，回到头部
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// 当 i 越过数组头部后，回到尾部
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return ((i + capacity(deque)) % capacity(deque));
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}
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/* 队首入队 */
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void pushFirst(ArrayDeque *deque, int num) {
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if (deque->queSize == capacity(deque)) {
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printf("双向队列已满\r\n");
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return;
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}
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// 队首指针向左移动一位
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// 通过取余操作，实现 front 越过数组头部回到尾部
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deque->front = dequeIndex(deque, deque->front - 1);
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// 将 num 添加到队首
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deque->nums[deque->front] = num;
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deque->queSize++;
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}
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/* 队尾入队 */
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void pushLast(ArrayDeque *deque, int num) {
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if (deque->queSize == capacity(deque)) {
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printf("双向队列已满\r\n");
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return;
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}
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// 计算尾指针，指向队尾索引 + 1
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int rear = dequeIndex(deque, deque->front + deque->queSize);
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// 将 num 添加至队尾
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deque->nums[rear] = num;
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deque->queSize++;
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}
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/* 访问队首元素 */
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int peekFirst(ArrayDeque *deque) {
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// 访问异常：双向队列为空
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assert(empty(deque) == 0);
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return deque->nums[deque->front];
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}
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/* 访问队尾元素 */
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int peekLast(ArrayDeque *deque) {
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// 访问异常：双向队列为空
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assert(empty(deque) == 0);
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int last = dequeIndex(deque, deque->front + deque->queSize - 1);
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return deque->nums[last];
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}
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/* 队首出队 */
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int popFirst(ArrayDeque *deque) {
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int num = peekFirst(deque);
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// 队首指针向后移动一位
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deque->front = dequeIndex(deque, deque->front + 1);
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deque->queSize--;
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return num;
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}
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/* 队尾出队 */
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int popLast(ArrayDeque *deque) {
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int num = peekLast(deque);
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deque->queSize--;
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return num;
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}
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/* Driver Code */
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int main() {
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/* 初始化队列 */
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int capacity = 10;
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ArrayDeque *deque = newArrayDeque(capacity);
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pushLast(deque, 3);
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pushLast(deque, 2);
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pushLast(deque, 5);
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printf("双向队列 deque = ");
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printArray(deque->nums, deque->queSize);
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/* 访问元素 */
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int peekFirstNum = peekFirst(deque);
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printf("队首元素 peekFirst = %d\r\n", peekFirstNum);
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int peekLastNum = peekLast(deque);
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printf("队尾元素 peekLast = %d\r\n", peekLastNum);
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/* 元素入队 */
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pushLast(deque, 4);
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printf("元素 4 队尾入队后 deque = ");
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printArray(deque->nums, deque->queSize);
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pushFirst(deque, 1);
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printf("元素 1 队首入队后 deque = ");
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printArray(deque->nums, deque->queSize);
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/* 元素出队 */
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int popLastNum = popLast(deque);
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printf("队尾出队元素 = %d ，队尾出队后 deque= ", popLastNum);
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printArray(deque->nums, deque->queSize);
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int popFirstNum = popFirst(deque);
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printf("队首出队元素 = %d ，队首出队后 deque= ", popFirstNum);
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printArray(deque->nums, deque->queSize);
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/* 获取队列的长度 */
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int dequeSize = size(deque);
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printf("双向队列长度 size = %d\r\n", dequeSize);
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/* 判断队列是否为空 */
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bool isEmpty = empty(deque);
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printf("队列是否为空 = %s\r\n", isEmpty ? "true" : "false");
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// 释放内存
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delArrayDeque(deque);
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return 0;
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}
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