单链表的简单实践

1.算法描述

数据结构与算法分析C++版：3.11

实现一个有序单链表，要求能返回链表大小，打印链表，检测x是否在链表（在则删除，否则添加）

 

2.实现

List.h

 

#ifndef LIST_H
#define LIST_H
#include <iostream>

template<class T>
struct Node{
	Node<T>* next;
	T data;
};

template<class T>
class List{
	public:
		List(){
			len = 0;
			first = new Node<T>;
			first->next = NULL;
		}
		List(T a[], int n){
			len = 0;
			first = new Node<T>;
			first->next = NULL;
			for(int i=0; i<n; i++){
				//有序插入元素
				insertData(a[i]);
			}
		}
		
		~List(){ release(); };
		
		//长度
		int length(){
			return len;
		}
		
		//长度(通过遍历链表)
		int getLength(){
			int length=0;
			Node<T>* r = first->next;
			while(r){
				 length++;
				 r = r->next;
			}
			return length;
		}
		
		//打印链表
		void printList(){
			Node<T>* r = first->next;
			std::cout<<"[";
			while(r){
				std::cout<<r->data<<" ";
				r = r->next;
			}
			std::cout<<"]"<<std::endl;
		}
		
		//检测元素是否存在
		bool isExsit(T x){
			Node<T> *r = first->next;
			bool b = true;
			while(r && r->data != x){
				r = r->next;
			}
			if(!r){ 
				b = false;
			}
			return b;
		}
		
		//添加或删除存在元素（存在则删除，不存在则添加）
		void findAddOrDelete(T x){
			Node<T> *r = first->next, *p=first, *t;
				while(r && r->data != x){
					p = r;
					r = r->next;
				}
				if(!r){ 
					insertData(x);	
				}else{
					//因为序列是有序的，删除连续相同的x
					while(r && r->data == x){
						t = r;
						p->next = t->next;
						delete t;
						r = p->next;
						len--;
					}
				}

		}
		
		//有序插入元素
		void insertData(T x){
				Node<T> *t = first->next, *p=first;
				Node<T> *r = new Node<T>;
				r->data = x;
				r->next = NULL;
				while(t && t->data < x){ 
					p = t;
					t = t->next;
				}
				p->next = r;
				r->next = t;
				len++;
		}
		
	private:
		Node<T>* first;
		int len;//存储链表长度
		void release(){
			Node<T> *r = first;
			while(r->next){
				Node<T> *t = r->next;
				r->next = t->next;
				delete t;
			}
			first->next = NULL;
		}
		
};

#endif

 main.cpp

 

#include <iostream>
#include "list.h"
using namespace std;

int main( ){
	int a[] = {3,11,2,8,4,5,3,6,8,8,8};
	
	List<int> l(a, 11);
	cout<<"length:"<<l.length()<<endl;
	l.printList();
	cout<<l.isExsit(32)<<" "<<l.isExsit(8)<<endl;
	l.findAddOrDelete(7);
	cout<<"length:"<<l.length()<<endl;
	l.printList();
	l.findAddOrDelete(8);
	cout<<"length:"<<l.length()<<endl;
	l.printList();
	
	return 0;
}

 

3.总结

难度没什么，主要是考察链表的基本操作，边界检查，尤其是使用指针的时候尤其注意，指针检查！

 

4.删除