个人笔记——栈

栈：先进后出；可用数组或链表实现

#include<stdlib.h>
#define MaxSize 5
typedef struct{
	int data[MaxSize];
	int top;
}Stack;
//初始化栈
void init(Stack *stack){
	stack->top=-1;
} 
//入栈操作
void push(Stack *stack,int value){
	if(stack->top==MaxSize-1){
		printf("栈已满，无法插入数据");
		return;
	}
	stack->top=stack->top+1;
	stack->data[stack->top]=value;
} 
//出栈操作
void pop(Stack *stack){
	if(stack->top==-1){
		printf("栈已空");
		return;
	}
	printf("%d",stack->data[stack->top]);
	stack->top--;
} 

链表实现栈

typedef struct node{
	int data;
	struct node *next;
}Node;
void init(Node *head){
	head->next=NULL;
} 
//入栈
void pushNode(Node *head,int value){
	Node *newNode = (Node *)malloc(sizeof(Node));
	newNode->data=value;
	newNode->next=NULL;
	newNode->next=head->next;
	head->next=newNode;
} 
//出栈
void popNode(Node *head){
	if(head->next==NULL){
		return;
	}
	Node *temp=head->next;
	printf("%d\n",temp->data);
	head->next=temp->next;
} 
int main(){
	Node *head=(Node *)malloc(sizeof(Node));
	init(head);
	pushNode(head,2);
	pushNode(head,4);
	pushNode(head,8);
	pushNode(head,11);
	popNode(head);
	popNode(head);
}

数组实现队列

判断入栈出栈的合法性

bool validateStackSequences(int* pushed, int pushedSize, int* popped, int poppedSize) {
     int *s=(int *)malloc(pushedSize*sizeof(int));
        int j=0;
        int top=-1;
        for(int i=0;i<poppedSize;i++){
            top++;
            s[top]=pushed[i];
            while(top!=-1 && s[top]==popped[j]){
                j++;
                top--;
            }
        }
        if(top!=-1){
            return false;
        }else{
            return true;
        }
    
}