数据结构习题--栈与队列

Posted 2021-11-29 susususu

双栈模拟队列
基本思路：队列是先进先出，栈是先进后出。用一个输入栈存进队元素，用一个输出栈将输出栈中的元素倒置，再出栈。这就实现了队列的先进先出。
注意：队满的条件为输入栈S1满且输出栈S2非空。并非输入栈满就代表队列满，因为如果输入栈满但输出栈空，可以将输出栈中的元素全部压入输出栈中，这就相当于队列没满，同时如果输出栈中有元素，则输入栈中的元素不能压入输出栈，如果压入就会打乱原有的序列。

#include<stdio.h>
#include<stdlib.h>
#define maxsize 30
typedef int datatype;
typedef struct{
    datatype data[maxsize];
    int top;
}SeqStack;

void Initial(SeqStack *S){
    S->top = -1;
} 

int StackIsFull(SeqStack *S){
    return S->top == maxsize-1;
}

int StackIsEmpty(SeqStack *S){
    return S->top == -1;
}

int StackPop(SeqStack *S){
    int k;
    if(StackIsEmpty(S))
       return 0;
    k = S->data[S->top--];
    return k;
}

int StackPush(SeqStack *S,datatype x){
    if(StackIsFull(S))
       return 0;
    S->data[++S->top]=x;
    return 1;
}
//判断队空 
int QueueIsEmpty(SeqStack *S1,SeqStack *S2){
    return StackIsEmpty(S1)&&StackIsEmpty(S2);  
} 
//进队列 
int EnQueue(SeqStack *S1,SeqStack *S2,datatype x){
    if(StackIsFull(S1)){  
        if(!StackIsEmpty(S2)){
            printf("用栈模拟的队列已满");
            return 0;
        }
        else{
            int k;
            while(!StackIsEmpty(S1)){
               k = StackPop(S1);
               StackPush(S2,k);
            }
        }
    }
    StackPush(S1,x);
    return 1; 
}
// 出队列 
int DeQueue(SeqStack *S1,SeqStack *S2){
    int  k;
    if(QueueIsEmpty(S1,S2)){
       printf("用栈模拟的队列已空");
       return 0;
    }
    else{
        if(StackIsEmpty(S2)){
            while(!StackIsEmpty(S1)){
               k = StackPop(S1);
               StackPush(S2,k);
            }
        }
    }
    return StackPop(S2);
}

void ImitateQueue(SeqStack *S1,SeqStack *S2){
    Initial(S1);
    Initial(S2);
    int x;
    printf("请输入进队元素：");
    scanf("%d",&x);
    while(x!=0){
        EnQueue(S1,S2,x);
        scanf("%d",&x);
    }
    printf("出队元素为：");
    while(!QueueIsEmpty(S1,S2)){
        int k;
        k = DeQueue(S1,S2);
        printf("%d",k);
    } 
}

main(){
    SeqStack *S1 = (SeqStack*)malloc(sizeof(SeqStack));
    SeqStack *S2 = (SeqStack*)malloc(sizeof(SeqStack));
    ImitateQueue(S1,S2);
}

铁道车厢调度问题
基本思路：用一个栈

#include<stdio.h>
#include<stdlib.h>
#define maxsize 30
typedef struct {
    char data[maxsize];
    int top;
}SeqStack;

void Initial(SeqStack *S){
    S->top = -1;
    } 
    
int IsFull(SeqStack *S){
    return S->top==maxsize-1;
}

int IsEmpty(SeqStack *S){
    return S->top==-1;
}

int Push(SeqStack *S,char x){
    if(IsFull(S))
       return 0;
    S->data[++S->top]=x;
    return 1;
}

char Pop(SeqStack *S){
    char c;
    if(IsEmpty (S))
       return 0;
       c = S->data[S->top];
    S->top--;
    return c;
}

void Railway(SeqStack *S){
    int i,j=0,n=9;
    char train[n] = {'H','S','H','H','S','H','S','S','H'},result[n];
    for(i=0;i<n;i++){
        if(train[i]=='S')
          result[j++]=train[i];
        else{
           Push(S,train[i]);
           }
    }

    while(!IsEmpty(S)){
        for(;j<n;j++){
            result[j]=Pop(S);
        }
    }
    for(j=0;j<n;j++){
        printf("%c",result[j]);
    }
    
}

main(){
    SeqStack *S = (SeqStack*)malloc(sizeof(SeqStack));
    Initial(S);
    printf("jjjj");
    Railway(S);
}