update,

2025-02-01 01:58:47 +08:00
parent b3da7aaef5
commit 04dbefcbaf
1259 changed files with 280657 additions and 0 deletions
--- a/it114105/itp4510/Lab03/Lab3.2/LinkedList.java
+++ b/it114105/itp4510/Lab03/Lab3.2/LinkedList.java
@@ -0,0 +1,132 @@
+
+public class LinkedList {
+
+    private ListNode head;
+    private ListNode tail;
+    private int count = 0;
+
+    public boolean isEmpty() {
+        return (head == null);
+    }
+
+    public void addToHead(Object item) {
+        if (isEmpty()) {
+            head = tail = new ListNode(item);
+        } else {
+            head = new ListNode(item, head);
+        }
+        count++;
+    }
+
+    public void addToTail(Object item) {
+        if (isEmpty()) {
+            head = tail = new ListNode(item);
+        } else {
+            tail.next = new ListNode(item);
+            tail = tail.next;
+        }
+        count++;
+    }
+
+    public Object removeFromHead() throws EmptyListException {
+        Object item = null;
+        if (isEmpty()) {
+            throw new EmptyListException();
+        }
+        item = head.data;
+        if (head == tail) {
+            head = tail = null;
+        } else {
+            head = head.next;
+        }
+        count--;
+        return item;
+    }
+
+    public Object removeFromtail() throws EmptyListException {
+
+        if (isEmpty()) {
+            throw new EmptyListException();
+        }
+        Object item = tail.data;
+        if (head == tail) {
+            head = tail = null;
+            return item;
+        }
+        ListNode current = head;
+        while (current.next != tail) {
+            current = current.next;
+        }
+        tail = current;
+        tail.next = null;
+        count--;
+        return item;
+    }
+
+    public String toString() {
+        String s = "[ ";
+        ListNode current = head;
+        while (current != null) {
+            s = s + current.data + " ";
+            current = current.next;
+        }
+        return s + " ]";
+    }
+
+    public int getCount() {
+        return count;
+    }
+
+    public Object getItemAt(int n) {
+        if (n < 0 || n >= count) {
+            throw new IndexOutOfBoundsException();
+        }
+        int currentPos = 0;
+        ListNode current = head;
+        while (currentPos <= (n - 1)) {
+            current = current.next;
+            currentPos++;
+        }
+        return current.data;
+    }
+
+    public void addItemAt(Object item, int n) {
+        if (isEmpty() || n == 0) {
+            addToHead(item);
+            return;
+        }
+        if (n >= count) {
+            addToTail(item);
+            return;
+        }
+        int currentPos = 0;
+        ListNode current = head;
+        while (currentPos < (n - 1)) {
+            current = current.next;
+            currentPos++;
+        }
+        ListNode newNode = new ListNode(item);
+        newNode.next = current.next;
+        current.next = newNode;
+        count++;
+
+    }
+    public Object removeItemAt(int n) throws EmptyListException{
+        if(n<0 || n>=count)
+            throw new IndexOutOfBoundsException();
+        if(n==0)
+            removeFromHead();
+        int currentPos=0;
+        ListNode current=head;
+        while(currentPos<(n-1)){
+            current = current.next;
+            currentPos++;
+        }
+        Object item = current.next.data;
+        current.next = current.next.next;
+        count--;
+        return item;
+        
+    }
+}
+