(9)数据结构-双端队列

原创

mb5dbc2345bf8de 2023-01-04 18:07:31 博主文章分类：数据结构 ©著作权

文章标签 数据结构 Data 双端队列循环队列 文章分类 数据结构与算法人工智能

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声明：本文用于学习使用，设计的双端队列手段稍有不同，但功能是完全一样的。不是pta里面的题目答案。能够独立写出来属于自己代码才是最重要的。思想是，队头入时，队头先移动数据再入，队尾入时直接入再移动。

1、简介

双端队列是一种能在队列两头进行操作的队列。在STL包里面存在dequeue是已经打包好的双端队列可直接使用

2、数据结构

typedef int ElemType;
typedef int Position;
struct QNode{
    ElemType *Data;
    Position front;
    Position rear;
    int MaxSize;
};
typedef struct QNode *PtrToQNode;
typedef PtrToQNode Deque;

3、函数实现

Deque InitQueue(int MaxSize);
bool Push(ElemType X, Deque D);     //队头入
ElemType Pop(Deque D);      //队头出
bool Inject(ElemType X, Deque D);   //队尾入
ElemType Eject(Deque D);    //队尾出
ElemType GetTop(Deque D);
void PrintDeQueue(Deque D);

3.1 初始化队列

Deque InitQueue(int MaxSize){
    Deque D = new QNode;
    //增加一个空间区分队空与队满，类似于循环队列
    MaxSize++;
    D->MaxSize = MaxSize;
    D->Data = new ElemType [MaxSize];
    fill(D->Data,D->Data+D->MaxSize,-1);
    D->front = D->rear = 0;
    return D;
}

3.2 队头入

bool Push(ElemType X, Deque D){
    if((D->rear+1)%D->MaxSize == D->front){
        cout << "Queue Full" << endl;
        return false;
    }else{
        D->front = (D->front-1 + D->MaxSize)%D->MaxSize;
        D->Data[D->front] = X;
        cout << "Push Successfully: " << X << endl;
        return true;
    }

}

3.3 队头出

ElemType Pop(Deque D){
    if(D->rear == D->front){
        cout << "Queue is Empty" << endl;
        return Error;
    }else{
        int t = D->Data[D->front];
        D->Data[D->front] = -1;
        D->front = (D->front+1)%D->MaxSize;
        cout << "Pop successfully:" << t << endl;
        return t;
    }
}

3.4 队尾入

bool Inject(ElemType X, Deque D){
    if((D->rear+1)%D->MaxSize == D->front){
        cout << "Queue Full" << endl;
        return false;
    }else{
        D->Data[D->rear] = X;
        cout << "Inject successfully:" << D->Data[D->rear] << endl;
        D->rear = (D->rear+1)%D->MaxSize;
        return true;
    }
}

3.5 队尾出

ElemType Eject(Deque D){
    if(D->rear == D->front){
        cout << "Queue Empty" << endl;
        return Error;
    }else{
        D->rear = (D->rear-1+D->MaxSize) % D->MaxSize;
        ElemType t = D->Data[D->rear];
        D->Data[D->rear] = -1;
        cout << "Eject successfully:" << t << endl;
        return t;
    }
}

3.6 获取头元素

//看你怎么理解GetTop了，我理解的是取头指针指向的位置。
ElemType GetTop(Deque D){
    if(D->rear == D->front){
        cout << "Queue Empty" << endl;
        return Error;
    }else{
        return D->Data[D->front];
    }
}

3.7 打印队列

void PrintDeQueue(Deque D){
    for (int i = 0; i < D->MaxSize; i++){
        cout << D->Data[i] << " ";
    }
    cout << endl;
}

4、完整代码

#include<iostream>
#include<algorithm>
using namespace std;

typedef int ElemType;
typedef int Position;
struct QNode{
    ElemType *Data;
    Position front;
    Position rear;
    int MaxSize;
};
typedef struct QNode *PtrToQNode;
typedef PtrToQNode Deque;

#define Error -1

Deque InitQueue(int MaxSize);
bool Push(ElemType X, Deque D);     //队头入
ElemType Pop(Deque D);      //队头出
bool Inject(ElemType X, Deque D);   //队尾入
ElemType Eject(Deque D);    //队尾出
ElemType GetTop(Deque D);
void PrintDeQueue(Deque D);

int main(){
    Deque D = InitQueue(5);
    cout << D->rear << " " << D->front << endl;
    cout << "Init Successfully" << endl;

    Push(2,D);
    Push(5,D);
    PrintDeQueue(D);
    Pop(D);
    Pop(D);
    //Pop(D);
    PrintDeQueue(D);


    Inject(33,D);
    Inject(44,D);
    Inject(55,D);
    //Inject(66,D);
    PrintDeQueue(D);
    Eject(D);
    Eject(D);
    PrintDeQueue(D);

    Push(3,D);
    PrintDeQueue(D);

    cout << "GetTop:" << GetTop(D) << endl;




    return 0;
}

Deque InitQueue(int MaxSize){
    Deque D = new QNode;
    //增加一个空间区分队空与队满，类似于循环队列
    MaxSize++;
    D->MaxSize = MaxSize;
    D->Data = new ElemType [MaxSize];
    fill(D->Data,D->Data+D->MaxSize,-1);
    D->front = D->rear = 0;
    return D;
}

bool Push(ElemType X, Deque D){
    if((D->rear+1)%D->MaxSize == D->front){
        cout << "Queue Full" << endl;
        return false;
    }else{
        D->front = (D->front-1 + D->MaxSize)%D->MaxSize;
        D->Data[D->front] = X;
        cout << "Push Successfully: " << X << endl;
        return true;
    }

}

void PrintDeQueue(Deque D){
    for (int i = 0; i < D->MaxSize; i++){
        cout << D->Data[i] << " ";
    }
    cout << endl;
}

ElemType Pop(Deque D){
    if(D->rear == D->front){
        cout << "Queue is Empty" << endl;
        return Error;
    }else{
        int t = D->Data[D->front];
        D->Data[D->front] = -1;
        D->front = (D->front+1)%D->MaxSize;
        cout << "Pop successfully:" << t << endl;
        return t;
    }
}

bool Inject(ElemType X, Deque D){
    if((D->rear+1)%D->MaxSize == D->front){
        cout << "Queue Full" << endl;
        return false;
    }else{
        D->Data[D->rear] = X;
        cout << "Inject successfully:" << D->Data[D->rear] << endl;
        D->rear = (D->rear+1)%D->MaxSize;
        return true;
    }
}

ElemType Eject(Deque D){
    if(D->rear == D->front){
        cout << "Queue Empty" << endl;
        return Error;
    }else{
        D->rear = (D->rear-1+D->MaxSize) % D->MaxSize;
        ElemType t = D->Data[D->rear];
        D->Data[D->rear] = -1;
        cout << "Eject successfully:" << t << endl;
        return t;
    }
}

//看你怎么理解GetTop了，我理解的是取头指针指向的位置。
ElemType GetTop(Deque D){
    if(D->rear == D->front){
        cout << "Queue Empty" << endl;
        return Error;
    }else{
        return D->Data[D->front];
    }
}