使用队列和堆栈来判断回文

判断一个字符串是否为回文，如"abcda"不是回文，”abcba“是回文。

这道题目非常简单，有许多种方法可以求解。在这里，特别使用堆栈和队列共同来解决这个问题。

代码清单：

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


#define MAXSIZE 20


typedef struct _stack{
char data[MAXSIZE];
int top;
} stack;

typedef struct _queue{
char data[MAXSIZE];
int front;
int rear;
} queue;




int isempty_queue(queue * xy)
{
return xy->front == xy->rear;
}

int isfull_queue(queue *xy)
{
return xy->rear >= MAXSIZE -1 ;
}


queue * init_queue(void)
{
    queue * tmp = (queue*) malloc( sizeof(queue) );
    tmp->front = tmp->rear = 0;

return tmp;
}


char dequeue(queue * xy)
{
if( isempty_queue(xy) )
    {
        printf("The queue is empty, cannon  dequeue.\n");
        exit(-5);
    }

return xy->data[xy->front++];
}

void inqueue(queue *xy, char value)
{
if( isfull_queue(xy) )
    {
        printf("The queue is full, cannnot enqueue.\n");
        exit(-6);
    }

    xy->data[xy->rear++] = value;
}


stack * init_stack(void)
{
    stack * tmp = (stack *) malloc( sizeof(stack) );
    tmp->top = 0;

return tmp;
}


int isempty_stack(stack *xy)
{
return xy->top == 0 ? 1 : 0;
}

int isfull_stack(stack *xy)
{
return xy->top >= MAXSIZE -1 ? 1: 0;
}



char  pop(stack *xy)
{
if( isempty_stack(xy) )
    {
        printf("cannot pop, the stack is empty.\n");
        exit(-2);
    }

return xy->data[--xy->top];
}

void push(stack *xy, char value)
{
if( isfull_stack(xy) )
    {
        printf("cannot push, the stack is full.\n");
        exit(-3);
    }

    xy->data[xy->top++] = value;
}



void judge(stack * a, queue *b, char str[], int len)
{
int i;
int flag = 0;
char temp_stack;
char temp_queue;

for(i = 0; i < len; i++)
    {
        push(a, str[i]);
        inqueue(b, str[i]);
    }

for(i = 0; i < len; i++)
    {
        temp_stack = pop(a);
        temp_queue = dequeue(b);

if(temp_stack != temp_queue)
        {
            printf("Not Palindrome.\n");
            flag = 1;
break;
        }
    }

if( !flag )
    {
        printf("The string is Palindrome.\n");
    }

}


int main()
{

    queue * stq = init_queue();
    stack * stk = init_stack();


char c[MAXSIZE];
char *cc;

    cc = fgets(c, MAXSIZE, stdin);


int len = strlen(c) - 1;

    judge(stk, stq, c, len);

return 0;
}