数据结构--线性表的链式存储结构（单链表完全实现）、单链表反转

阳光穿透心脏的1/2处 2021-08-14 01:41 610阅读 0赞

### 线性表的链式存储结构 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NvbGRfX19wbGF5_size_16_color_FFFFFF_t_70]

### 单链表节点类 ###

public class Node<T> { 
        //数据域，保存数据元素
        public T data;
    
        //地址域，引用后继节点
        public Node<T> next;
    
        public Node(){ 
            this(null,null);
        }
    
        public Node(T data, Node<T> next){ 
            this.data = data;
            this.next = next;
        }
    
        public String toString(){ 
            return this.data.toString();
        }
    
        public boolean equals(Object obj){ 
            return obj == this || obj instanceof Node && this.data.equals(((Node<T>)obj).data);
        }
    
    }

### 实现 ###

package pers.zhang.linearList;
    
    /** * @author zhang * @date 2020/1/14 - 10:23 * 单链表 */
    public class SinglyLinkedList<T> implements LinearList<T>{ 
        //头指针，指向单链表的头结点
        public Node<T> head;
    
        //默认构造，构造空单链表
        public SinglyLinkedList(){ 
            //创建头结点，data和next均为null
            this.head = new Node<T>();
        }
    
        //由指定数组中的多个对象构造单链表。采用尾插入构造单链表
        //若element==null，抛出空对象异常；若element.length==0，构造空链表
        public SinglyLinkedList(T[] element){ 
            this();//先创建空单链表，只有头节点
            Node<T> rear = this.head;//rear指向最后一个节点
            for(int i = 0; i < element.length; i++){ //element.length==0,构造空单链表
                rear.next = new Node<T>(element[i], null);//尾插入，创建节点链入rear之后
                rear = rear.next;//rear指向新的链表
            }
        }
    
        //由指定数组中的多个对象构造单链表，采用尾插入构造单链表，调用insertAfter()方法
    // public SinglyLinkedList(T[] element){ 
    // this();//创建空单链表，只有头结点
    // Node<T> rear = this.head;
    // for (int i = 0; i < element.length; i++)
    // rear = insertAfter(rear, element[i]);
    // }
    
        //由指定数组中的多个对象构造单链表，采用头插入构造反序的单链表
    // public SinglyLinkedList(T[] element){ 
    // this();//创建空单链表，只有头结点
    // for (int i=0; i<element.length; i++)
    // this.head.next = new Node<T>(element[i], this.head.next);
    // }
    
        //拷贝构造(深拷贝)
        public SinglyLinkedList(SinglyLinkedList<T> list){ 
            this();//构造空链表
            Node<T> rear = this.head;
            for(Node<T> p = list.head.next; p != null; p = p.next){ 
                rear.next = new Node<T>(p.data, null);
                rear = rear.next;
            }
        }
    
        //判断单链表是否为空
        @Override
        public boolean isEmpty() { 
            return this.head.next == null;
        }
    
        //返回单链表长度
        @Override
        public int length() { 
            int i = 0;
            Node<T> p = this.head.next;//从单链表第一个节点开始
            while(p != null){ //到最后一个
                i++;
                p = p.next;
            }
            return i;
        }
    
        //返回第i（i>=0）个元素，若i<0或大于表长则返回null，O(n)
        @Override
        public T get(int i) { 
            if(i >= 0){ 
                Node<T> p = this.head.next;
                for(int j = 0; p != null && j < i; j++){ 
                    p = p.next;
                }
                if(p != null)
                    return p.data;
            }
            return null;
        }
    
        //设置第i(i >= 0)个元素值为x。若i<0或大于表长则抛出越界异常；若x=null则不操作。O(n)
        @Override
        public void set(int i, T x) { 
            if(x == null)
                return;
            Node<T> p = this.head.next;
            for(int j = 0; p != null && j < i; j++)
                p = p.next;
            if(i >= 0 && p != null)
                p.data = x;
            else
                throw new IndexOutOfBoundsException(i + "");
        }
    
        //插入第i(i >= 0)个元素值为x。若x==null，不插入。
        //若i<0，插入x作为第0个元素；若i大于表长，插入x作为最后一个元素。O(n)
        @Override
        public void insert(int i, T x) { 
            if(x == null)//不能插入空对象
                return;
            Node<T> p = this.head.next;//p指向头结点
            for(int j = 0; p.next != null && i < j; j++)//查找第i个位置的前一个位置，作为插入位置
                p = p.next;
            p.next = new Node<T>(x, p.next);//插入节点
        }
    
    
        //将x对象插入在序号为i的节点，若操作成功返回新插入节点；否则返回null。O(n)
    // public Node<T> insert(int i, T x){ 
    // if(x == null)
    // return null;
    // Node<T> p = this.head.next;
    // for(int j = 0; p.next != null && j < i; j++)
    // p = p.next;
    // Node<T> q = new Node<T>(x, p.next);
    // p.next = q;
    // return q;
    // }
    
    
        //插入x作为p节点的后继节点，若操作成功返回新插入节点；否则返回null
        public Node<T> insertAfter(Node<T> p, T x){ 
            if(x == null || p == null)
                return null;
            Node<T> q = new Node<T>(x, p.next);
            p.next = q;
            return q;
        }
    
        //在单链表尾部追加节点
        @Override
        public void append(T x) { 
            insert(Integer.MAX_VALUE, x);//遍历一次
            insert(this.length(), x);//遍历两次
        }
    
    
        //删除第i个节点，返回被删除的对象。若i<0或i>表长，不删除，返回null。O(n)
        @Override
        public T remove(int i) { 
            if(i >= 0){ 
                Node<T> p = this.head.next;
                for(int j = 0; p.next != null && j < i; j++)//定位到待删除节点的前一个节点
                    p = p.next;
                if(p.next != null){ 
                    T old = p.next.data;//获得原来对象
                    p.next = p.next.next;//删除p的后继节点
                    return old;
                }
            }
            return null;
        }
    
        //删除p节点的后继节点，若操作成功返回删除节点；否则返回null。O(1)
        public Node<T> removoAfter(Node<T> p){ 
            if(p == null || p.next == null)
                return null;
            Node<T> q = p.next;
            p.next = q.next;
            return q;
        }
    
        //删除所有节点
        @Override
        public void removeAll() { 
            this.head.next = null;
        }
    
        //返回单链表所有元素的描述字符串，形式为“(,)”，覆盖Object类的toString()方法，O(n)
        public String toString(){ 
            String str = "(";
            for (Node<T> p = this.head.next; p != null; p = p.next)
            {    str += p.data.toString();
                if (p.next != null)
                    str += ",";//不是最后一个结点时后加分隔符
            }
            return str + ")";//空表返回()
        }
    
        //equals方法
        public boolean equals(Object obj){ 
            if(this == obj)//同一对象返回true
                return true;
            if(!(obj instanceof SinglyLinkedList))//非同类对象返回false
                return false;
            Node<T> p = this.head.next;
            Node<T> q = ((SinglyLinkedList<T>) obj).head.next;
            while(p != null && q != null && p.data.equals(q.data)){ //逐个比较
                p = p.next;
                q = q.next;
            }
            return p == null && q == null;
        }
    
        /* 以下4个方法提供迭代遍历单链表方式 */
        //返回单链表第一个元素
        public Node<T> getFirst(){ 
            return this.head.next;//空表返回null
        }
    
        //返回p的后继节点。O(1)
        public Node<T> getNext(Node<T> p){ 
            if(p == null || this.head.next == null)
                return null;
            return p.next;
        }
    
        //返回p的前驱节点。O(n)
        public Node<T> getPred(Node<T> p){ 
            if(p == null || this.head.next == p)//p为null，或者p为第一个节点则返回null
                return null;
            Node<T> front = this.head.next;
            while(front != null && front.next != p)
                front = front.next;
            return front;
        }
    
        //返回单链表的最后一个节点
        public Node<T> getLast(){ 
            Node<T> p = this.head.next;
            while(p != null && p.next != null)
                p = p.next;
            return p;
        }
    
        //求子表，返回从第i(i>=0)开始、长度为n(n>=0)的子表：深拷贝
        //若i<0或n<0，抛出异常；若i>表长或n-0，返回空链表；若n超长，返回至表尾的子表
        public SinglyLinkedList<T> sub(int i, int n){ 
            if(i < 0)
                throw new IndexOutOfBoundsException(i + "");//越界
            if(n < 0)
                throw new IllegalArgumentException(i + "");//无效参数
            Node<T> p = this.head.next;
            for(int j = 0; j < i && p != null; j++)//寻找子表表首节点
                p = p.next;
            SinglyLinkedList<T> list = new SinglyLinkedList<T>();
            Node<T> rear = list.head;//复制子表
            for(int j = 0; p != null && j < n; j++, p = p.next){ 
                rear.next = new Node<T>(p.data, null);
                rear = rear.next;
            }
            return list;//返回对象引用
        }
    
        //判断当前单链表是否包含list单链表的所有节点，判断无序的子集
        public boolean contain(SinglyLinkedList<T> list){ 
            for(Node<T> q = list.head.next; q != null; q = q.next){ 
                Node<T> p = head.next;
                while(p != null && !p.data.equals(q.data))
                    p = p.next;
                if(p == null)
                    return false;
            }
            return true;
        }
    
        //将list单链表中所有节点链接在当前单链表之后，并设置list为空
        public void concat(SinglyLinkedList<T> list){ 
            Node<T> rear = this.head;
            while(rear.next != null)
                rear = rear.next;//找到最后一个
            rear.next = list.head.next;//接上
            list.head.next = null;
        }
    
        //插入子表（深拷贝）
        //将list单链表中的所有节点赋复制插入到this单链表front节点之后
        public void insert(Node<T> front, SinglyLinkedList<T> list){ 
            for(Node<T> q = list.head.next; q != null; q = q.next){ 
                front.next = new Node<T>(q.data, front.next);
                front = front.next;
            }
        }
    
        //将list单链表中的所有节点赋值插入到this单链表第i个节点之前
        public void insert(int i, SinglyLinkedList<T> list){ 
            Node<T> p =  head;
            for(int j = 0; j < i && p.next != null; j++)
                p = p.next;
            this.insert(p, list);
        }
    
        //将list单链表中所有节点复制添加到当前单链表最后
        public void append(SinglyLinkedList<T> list){ 
            Node<T> rear = head;
            while(rear.next != null)
                rear = rear.next;
            insert(rear, list);
        }
    
        //删除从第i（≥0）个结点开始、长度为n（≥1）的子表
        //若i<0或n<0，抛出异常；若i>表长或n=0，不删除；若n超长，删除至表尾的子表
        public void remove(int i, int n){ 
            if(i < 0)
                throw new IndexOutOfBoundsException(i + "");    //抛出序号越界异常
            if(n < 0)
                throw new IllegalArgumentException(i + "");     //抛出无效参数异常
            Node<T> front = head;
            for (int j = 0; front != null && j < i; j++)//寻找待删除子表首结点的前驱结点
                front = front.next;
            if (front == null)//i越界，不删除
                return;
            Node<T> p = front.next;
            for (int j = 0; p != null && j < n; j++)//寻找待删除子表之后的结点
                p = p.next;
            front.next = p;//删除front后继结点至p前驱结点之间的子表
        }
    
        //返回this单链表首次出现的与pattern匹配的子表首结点，
        //查找不成功、当前或pattern单链表为空时，返回null
        public Node<T> index(SinglyLinkedList<T> pattern){ 
            return index(head.next, pattern);
        }
    
        //返回this单链表从start结点开始首次出现的与pattern匹配的子表首结点。
        //BF模式匹配。逐个结点比较，一重循环。
        public Node<T> index(Node<T> start, SinglyLinkedList<T> pattern){ 
            if (pattern.isEmpty())                             //若无此句，则返回start，错误
                return null;
            Node<T> p = start;
            Node<T> q = pattern.head.next;
            while (p != null && q != null)
            { 
                if (p.data.equals(q.data))                     //继续比较下一个结点
                {    p = p.next;
                    q = q.next;
                }
                else                                           //一次匹配失败
                {    start = start.next;                          //this继续匹配下个子表
                    p = start;
                    q = pattern.head.next;                       //pattern回退至表头
                }
            }
            if (q == null)                                       //匹配成功
                return start;                                  //返回匹配子表首结点
            return null;                                       //this空或全部匹配失败
        }
    
        //BF模式匹配。逐个子表匹配，二重循环。
    // public Node<T> index(Node<T> start, SinglyLinkedList<T> pattern){ 
    // if (pattern.isEmpty()) //若无此句，则返回start，错误
    // return null;
    // while (start!=null)
    // { 
    // Node<T> p=start, q=pattern.head.next;
    // while (p!=null && q!=null && p.data.equals(q.data))//继续比较下一个结点
    // { 
    // p=p.next;
    // q=q.next;
    // }
    // if (q==null) //匹配成功
    // return start; //返回匹配子表首结点
    // start=start.next;
    // }
    // return null; //this空或全部匹配失败
    // }
    
        //删除所有与pattern匹配的子表，BF模式匹配查找到再删除
        public void removeAll(SinglyLinkedList<T> pattern){ 
            System.out.print("将" + this.toString() + "中" + pattern.toString() + "全部删除");
            if (pattern.isEmpty())                             //若无此句，则死循环，错误
                return;
            Node<T> start = this.head.next, front = this.head;
            while (start != null){ 
                Node<T> p = start, q = pattern.head.next;
                while (p != null && q != null && p.data.equals(q.data)) { //一次匹配
                    p = p.next;
                    q = q.next;
                }
                if (q != null){                                    //匹配失败，进行下次匹配
                    front = start;
                    start = start.next;
                }else{                                            //匹配成功，删除该匹配子表
                    front.next = p;
                    start = p;
                }
            }
            System.out.println("的结果是" + this.toString());
        }
    
        //将this单链表中所有与pattern匹配的子表替换为dest子表。当dest为空时，相当于删除匹配子表。
        //包含BF模式匹配、删除匹配子表、复制插入子表算法
        public void replaceAll(SinglyLinkedList<T> pattern, SinglyLinkedList<T> dest){ 
            System.out.print("将" + this.toString() + "中" + pattern.toString() + "全部替换为" + dest.toString());
            if (pattern.isEmpty())                             //若无此句，则将dest插入到start结点之后，错误
                return;
            Node<T> start = this.head.next, front = this.head;     //front是start的前驱结点
            while (start != null){                         //start指向每次匹配的起始结点
                Node<T> p = start, q = pattern.head.next;
                while (p != null && q != null && p.data.equals(q.data)){ //一次匹配的多次比较
                    p = p.next;
                    q = q.next;
                }
                if (q != null){                                 //匹配失败，进行下次匹配
                    front = start;
                    start = start.next;
                }else{                                            //匹配成功，替换该匹配子表
                    front.next = p;
                    start = p;
                    Node<T> d = dest.head.next;
                    while (d != null){                         //将dest剩余结点深拷贝插入到this单链表front之后p之前
                        front.next = new Node<T>(d.data, p);
                        front = front.next;
                        d = d.next;
                    }
                }
            }
            System.out.println("的结果是" + this.toString());
        }
    
        //顺序查找关键字为key元素，返回首次出现的元素，若查找不成功返回null
        //key可以只包含关键字数据项，由T类的equals()方法提供比较对象相等的依据
        @Override
        public T search(T key) { 
            if(key == null)
                return null;
            for(Node<T> p = this.head.next; p != null; p = p.next)
                if(p.data.equals(key))
                    return p.data;
            return null;
        }
    
        //判断线性表是否包含关键字为key元素
        public boolean contain(T key){ 
            return this.search(key) != null;
        }
    
        //删除首次出现的值为x的结点，若没找到指定结点则不删除。O(n)
        public void remove(T x){ 
            if(x == null)
                return;
            Node<T> front = this.head;
            Node<T> p = front.next;
            while(p != null && !p.data.equals(x)){ 
                front = p;
                p = p.next;
            }
            if(p != null)
                front.next = p.next;//头删除、中间/尾删除
        }
    
        //删除所有值为x的结点
        public void removeAll(T x){ 
            if (x != null)
            { 
                Node<T> front = this.head, p = front.next;
                while (p != null) { 
                    if (p.data.equals(x)) { 
                        front.next = p.next;                   //删除p结点
                        p = front.next;
                    } else { 
                        front = p;
                        p = p.next;
                    }
                }
            }
        }
    
        //将首次出现的元素x替换为y，O(n)
        public void replace(T x, T y){ 
            if (x != null && y != null) { 
                for (Node<T> p = this.head.next; p != null; p = p.next)
                    if (p.data.equals(x)) { 
                        p.data = y;
                        return;
                    }
            }
        }
    
        //将所有值为x元素替换为y，O(n)
        public void replaceAll(T x, T y){ 
            if (x != null && y != null)
                for (Node<T> p = this.head.next;  p != null;  p = p.next)
                    if (p.data.equals(x))
                        p.data = y;
        }
    
    
        /** * 实现迭代器 */
        public java.util.Iterator<T> iterator(){ 
            return new SinglyIterator();
        }
    
        private class SinglyIterator implements java.util.Iterator<T>{ 
            //当前节点，初值为外部类单链表头结点
            Node<T> current = SinglyLinkedList.this.head;
    
            //当前结点的前驱结点
            Node<T> front = null;
    
    
            @Override
            public boolean hasNext() { 
                return this.current != null && this.current.next != null;
            }
    
            @Override
            public T next() { 
                if(this.hasNext()){ 
                    this.front = this.current;
                    this.current = this.current.next;
                    return this.current.data;
                }else{ 
                    throw new java.util.NoSuchElementException();
                }
            }
    
            @Override
            public void remove() { 
                if(this.front != null){ 
                    this.front.next = this.current.next;//删除当前节点
                    this.current = this.front;
                    this.front = null;//设置不能连续删除
                }else{ 
                    throw new java.lang.IllegalStateException();
                }
            }
        }
    
    
    
        /** * 递归方法 */
        /* public String toString() //返回单链表描述字符串 { return "("+ this.toString(this.head.next) +")"; } public String toString(Node<T> p) //返回从p结点开始的子表描述字符串，递归方法 { if (p==null) return ""; String str=p.data.toString(); if (p.next!=null) str+=", "; return str+this.toString(p.next); //递归调用 } public SinglyLinkedList(T[] element) //由指定数组中的多个对象构造单链表 { this(); //创建空单链表，只有头结点 this.head.next = create(element,0); } private Node<T> create(T[] element, int i) //由指定数组构造单链表，递归方法 { Node<T> p=null; if (i<element.length) { p = new Node<T>(element[i], null); p.next = create(element, i+1); } return p; } public SinglyLinkedList(SinglyLinkedList<T> list) //深拷贝，以单链表list构造新的单链表 { this(); this.head.next = copy(list.head.next); } private Node<T> copy(Node<T> p) //复制单链表，递归方法 { Node<T> q=null; if (p!=null) { q = new Node<T>(p.data, null); q.next = copy(p.next); } return q; } public int length() //返回单链表长度 { return length(this.head.next); } public int length(Node<T> p) //返回从p结点开始的单链表长度，递归方法 { if (p==null) return 0; return 1+length(p.next); //递归调用 } public boolean equals(Object obj) //比较两条单链表是否相等 { if (obj == this) return true; if (obj instanceof SinglyLinkedList) { SinglyLinkedList<T> list = (SinglyLinkedList<T>)obj; return equals(this.head.next, list.head.next); } return false; } private boolean equals(Node<T> p, Node<T> q) //比较两条单链表是否相等，递归方法 { return p==null && q==null || p!=null && q!=null && p.data.equals(q.data) && equals(p.next, q.next); } */
    }

### 测试 ###

package pers.zhang.linearList;
    
    import java.util.Iterator;
    
    /** * @author zhang * @date 2020/1/14 - 14:13 */
    public class SinglyLinkedList_ex { 
        public static void main(String args[])
        { 
    /* SinglyLinkedList<String> lista = new SinglyLinkedList<String>(); // for (int i=5; i>=0; i--) for (int i=0; i<=5; i++) lista.insert(i, new String((char)('A'+i)+"")); System.out.println("lista: "+lista.toString()+"，length()="+lista.length()); lista.set(3, new String((char)(lista.get(0).charAt(0)+32)+"")); lista.remove(0); lista.remove(3); // lista.remove(10); //抛出异常 System.out.println("lista: "+lista.toString()); */
    
            //深拷贝与比较相等
            SinglyLinkedList<Integer> list1 = new SinglyLinkedList<Integer>();   //空表
            System.out.println("list1: "+list1.toString());
            SinglyLinkedList<Integer> list2 = new SinglyLinkedList<Integer>();   //空表
            System.out.println("list2: "+list2.toString());
            System.out.println("list1.equals(list2)? "+list1.equals(list2));
    
            list1 = new SinglyLinkedList<Integer>(SinglyLinkedList_average.random(5));  //返回产生n个随机数的数组
            System.out.println("list1: "+list1.toString());
            list2 = new SinglyLinkedList<Integer>(list1);               //拷贝构造方法
            System.out.println("list2: "+list2.toString());
            System.out.println("list1.equals(list2)? "+list1.equals(list2));
    
            System.out.println("list1: "+list1.toString());
            list2.set(0, new Integer(list1.get(0).intValue()+100));
            list2.remove(list2.length()-1);                    //删除最后一个元素
            list2.remove(100);                                 //序号越界，没删除
            System.out.println("list2: "+list2.toString());
            System.out.println("list1.equals(list2)? "+list1.equals(list2));
    
            //10.2 实现迭代器
            Iterator<Integer> it = list1.iterator();      //获得单链表迭代器对象
            int sum=0;
            while (it.hasNext())
            { 
                int value=it.next().intValue();
                sum += value;
                System.out.print(value);
                if (it.hasNext())
                    System.out.print("+");
            }
            System.out.println("="+sum);
        }
    
    }

输出：

lista: (A, F, B, E, C, D)
    lista: (F, B, e, D)
    
            //深拷贝与比较相等
    list1: ()
    list2: ()
    list1.equals(list2)? true
    list1: (44, 10, 11, 20, 72)
    list2: (44, 10, 11, 20, 72)
    list1.equals(list2)? true
    list1: (44, 10, 11, 20, 72)
    list2: (144, 10, 11, 20)
    list1.equals(list2)? false
    44+10+11+20+72=157

### 单链表反转 ###

package pers.zhang.linearList;
    
    /** * @author zhang * @date 2020/1/14 - 14:18 */
    public class SinglyLinkedList_reverse { 
        //将单链表逆转，泛型方法，返回值类型前声明类型参数T
        public static <T> void reverse(SinglyLinkedList<T> list)
        { 
            Node<T> p=list.head.next, succ=null, front=null;   //head必须声明为public
            while (p!=null)
            { 
                succ = p.next;                                 //设置succ是p结点的后继结点
                p.next = front;                                //使p.next指向p结点的前驱结点
                front = p;
                p = succ;                                      //p向后走一步
            }
            list.head.next = front;
        }
    
        public static void main(String args[])
        { 
            String value[]={ "A","B","C","D","E","F"};
            SinglyLinkedList<String> list = new SinglyLinkedList<String>(value);
            System.out.println("list: "+list.toString());
            reverse(list);
            System.out.println("逆转后 "+list.toString());
        }
    }

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