Linked list

单恋表（^_^）

数组是由一系列相同数据类型，而且占用了连续的存储空间。

优点

1. 因为是连续的地址，查找方便，通过索引。

缺点

1. 进行删除或添加元素时，牵一发而动全身。
2. 以一开始定义一个数组的时候，就会限制该数组元素的个数。

单链表是线性数据结构，存储时不必连续的存储在一起，彼此通过pointers相互连接。

优点

1. 删除或添加元素时，高效
2. 可以随时添加元素，没有上限

缺点

1. 不能随机访问，需要通过头结点，挨家挨户的去查找所找的元素，也不能使用binary search
2. 因为包含 pointer & data，pointer 占用资源
3. Not cache friendly. Since array elements are contiguous locations, there is locality of reference which is not there in case of linked lists，简单来说就是没有数组的“索引”

先上C代码

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

struct node
{
    int data;
    struct node * next;
};
void printList(struct node * n)
{
    while(NULL != n)
    {
        printf("%d	", n->data);
        n = n->next;
    }

}
int main(void)
{
    struct node * frist = NULL;
    struct node * second = NULL;
    struct node * third = NULL;

    frist = (struct node *)malloc(sizeof(struct node));
    second = (struct node *)malloc(sizeof(struct node));
    third = (struct node *)malloc(sizeof(struct node));

    frist->data = 1;
    frist->next = second;

    second->data = 2;
    second->next = third;

    third->data = 3;
    third->next = NULL;

    printList(frist);
    return 0;
}

Java代码

package bird;

public class LinkedList {
    Node node;
    
    static class Node{
        
        Node next;
        int data;
        Node(int data){
            this.data = data;
            next = null;
        }
    }
    
    static void printList(Node n) {
        while(null != n) {
            System.out.println("data: "+n.data);
            n = n.next;
        }
    }
    
    public static void main(String[] args) {
        LinkedList head = new LinkedList();
        
        head.node = new Node(1);
        Node second = new Node(2);
        Node third = new Node(3);
        
        head.node.next = second;
        second.next = third;
        
        printList(head.node);
    }
}