链表

Author: tianqing.liang

04Stack-Queue/LoopQueue.dart

@@ -10,13 +10,21 @@ class LoopQueue<T> implements Queue<T>{
     arr = List.filled(10, false);
   }
 
+  LoopQueue.capcity(int capacity){
+    arr = List.filled(capacity+1, false);
+  }
+
   int getCapacity(){
-    int capacity =  arr!.length;
+    //目前这种方式浪费一个空间
+    int capacity =  arr!.length-1;
     return capacity;
   }
 
   @override
   dequeue() {
+    if(isEmpty()){
+      throw Exception("Cannot dequeue from an empty queue");
+    }
     T ret = arr![front];
     arr![front] = null;
     front = (front + 1) % arr!.length;
@@ -29,7 +37,7 @@ class LoopQueue<T> implements Queue<T>{
 
   void resize(int newCapacity){
 
-    List? newArr = List.filled(newCapacity, false);
+    List? newArr = List.filled(newCapacity+1, false);
     for(int i = 0 ; i < arr!.length ; i ++){
       newArr[i] = arr![(i + front) % arr!.length];
     }

04Stack-Queue/Main.dart

@@ -10,16 +10,16 @@ void main(){
 //  }
 //  stack.pop();
 //
-  ArrayQueue queue = new ArrayQueue();
-  for(int i = 0 ; i < 20 ; i ++){
-    queue.enqueue(i);
-    print(queue);
-    if(i % 3 == 2){
-      print('----出栈头部元素-----');
-      queue.dequeue();
-      print(queue);
-    }
-  }
+//  ArrayQueue queue = new ArrayQueue();
+//  for(int i = 0 ; i < 20 ; i ++){
+//    queue.enqueue(i);
+//    print(queue);
+//    if(i % 3 == 2){
+//      print('----出栈头部元素-----');
+//      queue.dequeue();
+//      print(queue);
+//    }
+//  }
 
   LoopQueue<int> loopQueue = new LoopQueue<int>();
   for(int i = 0 ; i < 30 ; i ++){

05LinkedList/LinkedList.dart

@@ -0,0 +1,70 @@
+class LinkedList<T>{
+
+   late _Node _head;
+   late int _size;
+
+   LinkedList(){
+      _head = new _Node.empty();
+      _size = 0;
+   }
+
+   int getSize(){
+      return _size;
+   }
+
+   bool isEmpty(){
+      return _size == 0;
+   }
+
+   addFirst(T t){
+//      _Node _node =new _Node.head(t);
+//      _node.next = _head;
+//      _head = _node;
+
+      _head = new _Node.all(t, _head);
+      _size++;
+   }
+
+   //在链表的index位置添加新的元素e
+   add(int index,T t){
+      if(index<0||index>_size){
+         throw Exception("Add Failed,Illegal index");
+      }
+      if(index == 0){
+         addFirst(t);
+      }else{
+         _Node prev = _head;
+         for(var i =0;i<index-1;i++){
+            prev = prev.next;
+         }
+         _Node _node = new _Node.head(t);
+         _node.next = prev.next;
+         prev.next = _node;
+         _size++;
+      }
+   }
+
+   addLast(T t){
+      add(_size, t);
+   }
+}
+//节点
+class _Node<T>{
+   late _Node next;
+   late T t;
+
+   _Node.empty();
+
+   _Node.all(this.t,this.next);
+
+   factory _Node.head(T t){
+      dynamic i ;
+      var result = new _Node.all(t, i);
+      return result;
+   }
+
+   @override
+  String toString() {
+    return t.toString();
+  }
+}

05LinkedList/main.dart

@@ -0,0 +1,5 @@
+import 'LinkedList.dart';
+
+void main(){
+
+}