用OC基于数组实现循环队列

一、简言

使用数组实现循环队列时，始终会有一个空余的位置预留着，作为一个判决队列已满的条件(当然也可以采用其他方式)。在前面已经用C++介绍了基本的算法，可以去回顾一下https://www.cnblogs.com/XYQ-208910/p/11700048.html。光说不练嘴把式，现在本文使用OC面向对象的思想来实现一下。

 

二、代码

ArrayQueue

//
//  ArrayQueue.h
//  运行时
//
//  Created by 夏远全 on 2019/10/19.
//

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface ArrayQueue : NSObject

/**
 构造一个循环队列
 @param capacity 队列容量
 @return 队列
 */
+(instancetype)constrcutArrayQueueWithCapacity:(int)capacity;

/**
 入队列
 @param element 元素
 */
-(void)enQueueWithElement:(id)element;

/**
 出队列
 @return 元素
 */
-(id)deQueueElement;

/**
 队列是否为空
 @return 布尔值
 */
-(BOOL)isEmpty;

/**
 队列是否已满
 @return 布尔值
 */
-(BOOL)isFull;

/**
 获取元素个数
 @return 个数
 */
-(int)eleCount;

@end

NS_ASSUME_NONNULL_END

//
//  ArrayQueue.m
//  运行时
//
//  Created by 夏远全 on 2019/10/19.
//

#import "ArrayQueue.h"

@interface ArrayQueue ()
@property (nonatomic, strong) NSMutableArray *array;
@property (nonatomic, assign) int     front;
@property (nonatomic, assign) int     rear;
@property (nonatomic, assign) int     capacity;
@end

@implementation ArrayQueue

/**
 构造一个循环队列
 @param capacity 队列容量
 @return 队列
 */
+(instancetype)constrcutArrayQueueWithCapacity:(int)capacity {

    ///断言一下
    assert(capacity>);

    ArrayQueue *arrayQueue = [[ArrayQueue alloc] init];
    arrayQueue.array = [NSMutableArray array]; //初始化容器
    arrayQueue.capacity = capacity;            //初始化容量
    arrayQueue.front = arrayQueue.rear = ;    //初始化首尾指针
    return arrayQueue;
}

/**
 入队列
 @param element 元素
 */
-(void)enQueueWithElement:(id)element {

    ///判断队列是否已满
    if ([self isFull]) {
        NSLog(@"队列已满，元素%@不能被入列, front = %d , rear = %d", element, self.front, self.rear);
        return;
    }

    ///插入新元素
    self.array[self.rear] = element;

    ///更新队尾指针
    self.rear  = (self.rear + ) % self.capacity;

    NSLog(@"入队列的元素 = %@, front = %d , rear = %d", element, self.front, self.rear);
}

/**
 出队列
 @return 元素
 */
-(id)deQueueElement {

    ///判断队列是否已空
    if ([self isEmpty]) {
        NSLog(@"队列已空, front = %d , rear = %d", self.front, self.rear);
        return nil;
    }

    ///取出队头的元素
    id element = self.array[self.front];

    ///更新队头指针
    self.front = (self.front + ) % self.capacity;

    NSLog(@"出队列的元素 = %@, front = %d , rear = %d", element, self.front, self.rear);

    return element;
}

/**
 队列是否为空
 @return 布尔值
 */
-(BOOL)isEmpty {

    if (self.front == self.rear) {
        return YES;
    }
    return NO;
}

/**
 队列是否已满
 @return 布尔值
 */
-(BOOL)isFull {

    if (self.front == (self.rear + ) % self.capacity) {
        return YES;
    }
    return NO;
}

/**
 获取元素个数
 @return 个数
 */
-(int)eleCount {

    int eleCount = (self.rear - self.front + self.capacity) % self.capacity;
    NSLog(@"队列元素个数 = %d", eleCount);
    return eleCount;
}

@end

三、结果

测试

-(void)test_DataStructure_ArrayQueue {

    /// 构造循环队列
    ArrayQueue *arrayQueue = [ArrayQueue constrcutArrayQueueWithCapacity:];

    /// enter Queue 入队列
    [arrayQueue enQueueWithElement:@()];
    [arrayQueue enQueueWithElement:@()];
    [arrayQueue enQueueWithElement:@()];
    [arrayQueue enQueueWithElement:@()];
    [arrayQueue enQueueWithElement:@()];

    /// 全部入队后 get eleCount 元素个数
    [arrayQueue eleCount];

    /// deque Queue 出队列
    [arrayQueue deQueueElement];
    [arrayQueue deQueueElement];
    [arrayQueue deQueueElement];
    [arrayQueue deQueueElement];
    [arrayQueue deQueueElement];

    /// 全部出队后  get eleCount 元素个数
    [arrayQueue eleCount];

}

打印

-- ::57.323138+ 运行时[:] 入队列的元素 = , front =  , rear =
-- ::57.323314+ 运行时[:] 入队列的元素 = , front =  , rear =
-- ::57.323435+ 运行时[:] 入队列的元素 = , front =  , rear =
-- ::57.323544+ 运行时[:] 入队列的元素 = , front =  , rear =
-- ::57.323639+ 运行时[:] 队列已满，元素100不能被入列, front =  , rear =
-- ::57.323721+ 运行时[:] 队列元素个数 =
-- ::57.323844+ 运行时[:] 出队列的元素 = , front =  , rear =
-- ::57.323945+ 运行时[:] 出队列的元素 = , front =  , rear =
-- ::57.324033+ 运行时[:] 出队列的元素 = , front =  , rear =
-- ::57.324140+ 运行时[:] 出队列的元素 = , front =  , rear =
-- ::57.324245+ 运行时[:] 队列已空, front =  , rear =
-- ::57.324344+ 运行时[:] 队列元素个数 =