数据结构与算法 | 栈

一、栈

定义：先入后进的操作约束的有穷线性表

操作：

Stack CreateStack( int MaxSize ) //生成空堆栈，其最大长度为MaxSize；
int IsFull( Stack S, int MaxSize ) //判断堆栈S是否已满；
void Push( Stack S, ElementType item ) //将元素item压入堆栈；
int IsEmpty ( Stack S ) //判断堆栈S是否为空；
ElementType Pop( Stack S ) //删除并返回栈顶元素；

二、顺序存储实现

用数组实现，表示：

const int MaxSize =100; //栈的容量
typedef struct StackNode* stack;
struct StackNode{
    int Data[MaxSize];
    int top;
};
stack s;

1、创建空栈

stack CreatStack(){
    stack s = new StackNode();
    s->top = -1;
    return s;
}

2、判断栈是否已经满了

bool IsFull(stack s,int MaxSize){
    if（s->top==MaxSize-1)
        reutrn true;
    return false;
}

3、入栈

void push(stack s,int X){
    if(IsFull(s)){
        cout<<"stack is full"<<endl;
        return;
    }
    s->Data[s->top+1] = X;
    s->top++;
}

4、判断栈是否空

bool IsEmpty(stack s){
    if(s->top==-1)
        return true;
    return false;
}

5、出栈

int pop(stack s){
    if(IsEmpty(s))
        throw "the stack is empty";
    return s->Data[s->top--];
}

三、链表实现

表示：

typedef struck StackNode*stack;
struck StackNode{
    int Data;
    StackNode* Next;
}

1、创建空栈

stack CreatStack(){
    stack s = new StackNode();
    s->Next =nullptr;
    return s;
}

2、判断栈是否为空

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bool IsEmpty(stack s){
    if(s->Next==nullptr)
        return true;
    return false;
}

3、入栈

void push(stack s,int X){
    stack NewNode = new StactNode();
    NewNode->Data = X;
    NewNode->Next = s->Next;
    s->Next = NewNode;
}

4、出栈

int pop(stack s){
    if(IsEmpty(s))
        throw "the stack is empty";
    stack p = s->Next;
    s->Next = p->Next;
    int top = p->Data;
    delete p;
    p = nullptr;
    return top;
}