双栈实现一队列/双队列实现一栈 C语言实现

#include <stdio.h>
#include <stdlib.h>

#define N 10

int a[N];
int pa = 0;
int b[N];
int pb = 0;

void pusha(int e)
{
        if(pa == N)
        {
                printf("a stack overflow");
                exit(1);
        }
        a[pa++] = e;
}

int popa()
{
        if(pa == 0)
        {
                printf("a no element");
                exit(1);
        }
        pa--;
        return a[pa];
}

void pushb(int e)
{
        if(pb == N)
        {
                printf("b stack overflow");
                exit(1);
        }
        b[pb++] = e;
}

int popb()
{
        if(pb == 0)
        {
                printf("b no element");
                exit(1);
        }
        pb--;
        return b[pb];
}

void inqueue(int e)
{
    int i = pb -1;
    while(i>=0)
    {
            pusha(popb());
            i--;
    }
    pusha(e);
}

int outqueue()
{
        int i = pa - 1;
        while(i>=0)
        {
            pushb(popa());
            i--;
        }
        return popb();
}

int main()
{
    inqueue(1);
    inqueue(2);
    inqueue(3);
    inqueue(4);
    inqueue(5);
    printf("%d\n", outqueue());
    inqueue(6);
    printf("%d\n", outqueue());
    printf("%d\n", outqueue());
    inqueue(7);
    printf("%d\n", outqueue());
    inqueue(8);
    inqueue(9);
    inqueue(10);
    printf("%d\n", outqueue());
    printf("%d\n", outqueue());
    printf("%d\n", outqueue());
    printf("%d\n", outqueue());
    printf("%d\n", outqueue());
    printf("%d\n", outqueue());
    printf("%d\n", outqueue());

    return 0;
}


#include <stdio.h>
#include <stdlib.h>

typedef void (*enqueue)(int);
typedef int (*dequeue)();
typedef int (*queueempty)();

#define N 10
int q1[N];
int head1 = 0, tail1 = 0;

// head must point to an empty space

// so queue's capacity is N - 1

void enqueue1(int e)
{
        int t = (tail1 + 1) % N;
        if (t == head1)
        {
            printf("queue1 overflow\n");
            exit(1);
        }
        q1[t] = e;
        tail1 = t;
}

int dequeue1()
{
        if (queue1empty())
        {
                printf("queue1 empty\n");
                exit(1);
        }
        head1 = (head1 + 1) % N;
        return q1[head1];
}

int queue1empty()
{
        if (head1 == tail1)
        {
                return 1;
        }
        return 0;
}

int q2[N];
int head2 = 0, tail2 = 0;

void enqueue2(int e)
{
        int t = (tail2 + 1) % N;
        if (t == head2)
        {
            printf("queue2 overflow\n");
            exit(1);
        }
        q2[t] = e;
        tail2 = t;
}

int dequeue2()
{
        if (queue2empty())
        {
                printf("queue2 empty\n");
                exit(1);
        }
        head2 = (head2 + 1) % N;
        return q2[head2];
}

int queue2empty()
{
        if (head2 == tail2)
        {
                return 1;
        }
        return 0;
}

// queue1 is main.

enqueue EN_M = enqueue1;     // main

dequeue DE_M = dequeue1;
queueempty EMP_M = queue1empty;

enqueue EN_V = enqueue2;     // vice

dequeue DE_V = dequeue2;
queueempty EMP_V = queue2empty;

void swap()
{
        enqueue e1 = EN_M;
        dequeue d1 = DE_M;
        queueempty q1 = EMP_M;

        EN_M = EN_V;
        DE_M = DE_V;
        EMP_M = EMP_V;

        EN_V = e1;
        DE_V = d1;
        EMP_V = q1;
}

void push(int e)
{
        if (!EMP_V())
        {
                while (!EMP_M())
                {
                        EN_V(DE_M());
                }
                swap();
        }
        EN_V(e);
}

int pop()
{
        if (!EMP_V())
        {
                return DE_V();
        }
        return DE_M();
}

int main()
{
        /*
        // test queue1
        ENQUEUE = enqueue1;
        DEQUEUE = dequeue1;
        ENQUEUE(1);
        ENQUEUE(2);
        ENQUEUE(3);
        ENQUEUE(4);
        ENQUEUE(5);
        ENQUEUE(6);
        ENQUEUE(7);
        ENQUEUE(8);
        ENQUEUE(9);
        printf("%d\n", DEQUEUE());
        printf("%d\n", DEQUEUE());
        printf("%d\n", DEQUEUE());
        printf("%d\n", DEQUEUE());
        printf("%d\n", DEQUEUE());
        ENQUEUE(7);
        ENQUEUE(8);
        ENQUEUE(9);
        printf("%d\n", DEQUEUE());
        printf("%d\n", DEQUEUE());
        printf("%d\n", DEQUEUE());
        */
        push(1);
        push(2);
        push(3);
        push(4);
        push(5);
        push(6);
        push(7);
        push(8);
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        push(9);
        push(10);
        push(11);
        push(12);
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        push(13);
        printf("%d\n", pop());
        push(13);
        push(13);
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());
        printf("%d\n", pop());

        return 0;
}