本周任务：
1.lecture10、11、12、13
2.lab4&hw4
3.pj1尽量
7.24
lecture10完成
lab4打卡：
DList1：
/* DList1.java */
/**
* A DList1 is a mutable doubly-linked list. (No sentinel, not
* circularly linked.)
*/
public class DList1 {
/**
* head references the first node.
* tail references the last node.
*
* DO NOT CHANGE THE FOLLOWING FIELD DECLARATIONS.
*/
protected DListNode1 head;
protected DListNode1 tail;
protected long size;
/* DList1 invariants:
* 1) head.prev == null.
* 2) tail.next == null.
* 3) For any DListNode1 x in a DList, if x.next == y and x.next != null,
* then y.prev == x.
* 4) For any DListNode1 x in a DList, if x.prev == y and x.prev != null,
* then y.next == x.
* 5) The tail can be accessed from the head by a sequence of "next"
* references.
* 6) size is the number of DListNode1s that can be accessed from the
* head by a sequence of "next" references.
*/
/**
* DList1() constructor for an empty DList1.
*/
public DList1() {
head = null;
tail = null;
size = 0;
}
/**
* DList1() constructor for a one-node DList1.
*/
public DList1(int a) {
head = new DListNode1();
tail = head;
head.item = a;
size = 1;
}
/**
* DList1() constructor for a two-node DList1.
*/
public DList1(int a, int b) {
head = new DListNode1();
head.item = a;
tail = new DListNode1();
tail.item = b;
head.next = tail;
tail.prev = head;
size = 2;
}
/**
* insertFront() inserts an item at the front of a DList1.
*/
public void insertFront(int i) {
DListNode1 NewNode=new DListNode1(i);
NewNode.next=head;
head=NewNode;
size++;
if(size==1) {
tail=head;
tail.prev=null;
}else if(size==2) {
tail.prev=head;
}
// Your solution here.
}
/**
* removeFront() removes the first item (and node) from a DList1. If the
* list is empty, do nothing.
*/
public void removeFront() {
// Your solution here.
if(size!=0) {
if(size==1) {
head=null;
tail=null;
}else if(size==2) {
head.prev=null;
head.next=null;
tail.next=null;
tail.prev=null;
head=tail;
}
size--;
}
}
/**
* toString() returns a String representation of this DList.
*
* DO NOT CHANGE THIS METHOD.
*
* @return a String representation of this DList.
*/
public String toString() {
String result = "[ ";
DListNode1 current = head;
while (current != null) {
result = result + current.item + " ";
current = current.next;
}
return result + "]";
}
public static void main(String[] args) {
// DO NOT CHANGE THE FOLLOWING CODE.
DList1 l = new DList1();
System.out.println("### TESTING insertFront ###\nEmpty list is " + l);
l.insertFront(9);
System.out.println("\nInserting 9 at front.\nList with 9 is " + l);
if (l.head == null) {
System.out.println("head is null.");
} else {
if (l.head.item != 9) {
System.out.println("head.item is wrong.");
}
if (l.head.prev != null) {
System.out.println("head.prev is wrong.");
}
}
if (l.tail == null) {
System.out.println("tail is null.");
} else {
if (l.tail.item != 9) {
System.out.println("tail.item is wrong.");
}
if (l.tail.next != null) {
System.out.println("tail.next is wrong.");
}
}
if (l.size != 1) {
System.out.println("size is wrong.");
}
l.insertFront(8);
System.out.println("\nInserting 8 at front.\nList with 8 and 9 is " + l);
if (l.head == null) {
System.out.println("head is null.");
} else {
if (l.head.item != 8) {
System.out.println("head.item is wrong.");
}
if (l.head.prev != null) {
System.out.println("head.prev is wrong.");
}
if (l.head.next != l.tail) {
System.out.println("head.next is wrong.");
}
}
if (l.tail == null) {
System.out.println("tail is null.");
} else {
if (l.tail.item != 9) {
System.out.println("tail.item is wrong.");
}
if (l.tail.next != null) {
System.out.println("tail.next is wrong.");
}
if (l.tail.prev != l.head) {
System.out.println("tail.prev is wrong.");
}
}
if (l.size != 2) {
System.out.println("size is wrong.");
}
l = new DList1(1, 2);
System.out.println("\n\n### TESTING removeFront ###\nList with 1 and 2 is "
+ l);
l.removeFront();
System.out.println("\nRemoving front node.\nList with 2 is " + l);
if (l.head.item != 2) {
System.out.println("head.item is wrong.");
}
if (l.head.prev != null) {
System.out.println("head.prev is wrong.");
}
if (l.tail.item != 2) {
System.out.println("tail.item is wrong.");
}
if (l.tail.next != null) {
System.out.println("tail.next is wrong.");
}
if (l.size != 1) {
System.out.println("size is wrong.");
}
l.removeFront();
System.out.println("\nRemoving front node.\nEmpty list is " + l);
if (l.head != null) {
System.out.println("head is wrong.");
}
if (l.tail != null) {
System.out.println("tail is wrong.");
}
if (l.size != 0) {
System.out.println("size is wrong.");
}
l.removeFront();
System.out.println("\nRemoving front node.\nEmpty list is " + l);
if (l.head != null) {
System.out.println("head is wrong.");
}
if (l.tail != null) {
System.out.println("tail is wrong.");
}
if (l.size != 0) {
System.out.println("size is wrong.");
}
}
}
运行结果：
DList2：
/* DList2.java */
/**
* A DList2 is a mutable doubly-linked list. Its implementation is
* circularly-linked and employs a sentinel (dummy) node at the head
* of the list.
*/
public class DList2 {
/**
* head references the sentinel node.
*
* DO NOT CHANGE THE FOLLOWING FIELD DECLARATIONS.
*/
protected DListNode2 head;
protected long size;
/* DList2 invariants:
* 1) head != null.
* 2) For any DListNode2 x in a DList2, x.next != null.
* 3) For any DListNode2 x in a DList2, x.prev != null.
* 4) For any DListNode2 x in a DList2, if x.next == y, then y.prev == x.
* 5) For any DListNode2 x in a DList2, if x.prev == y, then y.next == x.
* 6) size is the number of DListNode2s, NOT COUNTING the sentinel
* (denoted by "head"), that can be accessed from the sentinel by
* a sequence of "next" references.
*/
/**
* DList2() constructor for an empty DList2.
*/
public DList2() {
head = new DListNode2();
head.item = Integer.MIN_VALUE;
head.next = head;
head.prev = head;
size = 0;
}
/**
* DList2() constructor for a one-node DList2.
*/
public DList2(int a) {
head = new DListNode2();
head.item = Integer.MIN_VALUE;
head.next = new DListNode2();
head.next.item = a;
head.prev = head.next;
head.next.prev = head;
head.prev.next = head;
size = 1;
}
/**
* DList2() constructor for a two-node DList2.
*/
public DList2(int a, int b) {
head = new DListNode2();
head.item = Integer.MIN_VALUE;
head.next = new DListNode2();
head.next.item = a;
head.prev = new DListNode2();
head.prev.item = b;
head.next.prev = head;
head.next.next = head.prev;
head.prev.next = head;
head.prev.prev = head.next;
size = 2;
}
/**
* insertFront() inserts an item at the front of a DList2.
*/
public void insertFront(int i) {
DListNode2 NewNode=new DListNode2(i);
NewNode.prev=head;
NewNode.next=head.next;
head.next=NewNode;
head.next.next.prev=NewNode;
size++;
// Your solution here.
}
/**
* removeFront() removes the first item (and first non-sentinel node) from
* a DList2. If the list is empty, do nothing.
*/
public void removeFront() {
head.next=head.next.next;
head.next.prev=head;
if(size!=0) {
size--;
}
// Your solution here.
}
/**
* toString() returns a String representation of this DList.
*
* DO NOT CHANGE THIS METHOD.
*
* @return a String representation of this DList.
*/
public String toString() {
String result = "[ ";
DListNode2 current = head.next;
while (current != head) {
result = result + current.item + " ";
current = current.next;
}
return result + "]";
}
public static void main(String[] args) {
// DO NOT CHANGE THE FOLLOWING CODE.
DList2 l = new DList2();
System.out.println("### TESTING insertFront ###\nEmpty list is " + l);
l.insertFront(9);
System.out.println("\nInserting 9 at front.\nList with 9 is " + l);
if (l.head.next.item != 9) {
System.out.println("head.next.item is wrong.");
}
if (l.head.next.prev != l.head) {
System.out.println("head.next.prev is wrong.");
}
if (l.head.prev.item != 9) {
System.out.println("head.prev.item is wrong.");
}
if (l.head.prev.next != l.head) {
System.out.println("head.prev.next is wrong.");
}
if (l.size != 1) {
System.out.println("size is wrong.");
}
l.insertFront(8);
System.out.println("\nInserting 8 at front.\nList with 8 and 9 is " + l);
if (l.head.next.item != 8) {
System.out.println("head.next.item is wrong.");
}
if (l.head.next.prev != l.head) {
System.out.println("head.next.prev is wrong.");
}
if (l.head.prev.item != 9) {
System.out.println("head.prev.item is wrong.");
}
if (l.head.prev.next != l.head) {
System.out.println("head.prev.next is wrong.");
}
if (l.head.next.next != l.head.prev) {
System.out.println("l.head.next.next != l.head.prev.");
}
if (l.head.prev.prev != l.head.next) {
System.out.println("l.head.prev.prev != l.head.next.");
}
if (l.size != 2) {
System.out.println("size is wrong.");
}
l = new DList2(1, 2);
System.out.println("\n\n### TESTING removeFront ###\nList with 1 and 2 is "
+ l);
l.removeFront();
System.out.println("\nList with 2 is " + l);
if (l.head.next.item != 2) {
System.out.println("head.next.item is wrong.");
}
if (l.head.next.prev != l.head) {
System.out.println("head.next.prev is wrong.");
}
if (l.head.prev.item != 2) {
System.out.println("head.prev.item is wrong.");
}
if (l.head.prev.next != l.head) {
System.out.println("head.prev.next is wrong.");
}
if (l.size != 1) {
System.out.println("size is wrong.");
}
l.removeFront();
System.out.println("\nEmpty list is " + l);
if (l.head.next != l.head) {
System.out.println("head.next is wrong.");
}
if (l.head.prev != l.head) {
System.out.println("head.prev is wrong.");
}
if (l.size != 0) {
System.out.println("size is wrong.");
}
l.removeFront();
System.out.println("\nEmpty list is " + l);
if (l.head.next != l.head) {
System.out.println("head.next is wrong.");
}
if (l.head.prev != l.head) {
System.out.println("head.prev is wrong.");
}
if (l.size != 0) {
System.out.println("size is wrong.");
}
}
}
运行结果：
时间： 2024-10-02 20:53:08