star node next ray datanode lse util class null

節點類

public class ListNode {
int data;//數據
ListNode next;//指針
public ListNode(int x){data=x;}
public int getData() {
return data;
}
public void setData(int data) {
this.data = data;
}
public ListNode getNext() {
return next;
}
public void setNext(ListNode next) {
this.next = next;
}

}

節點操作：
public class ListNodeUtil { //鏈表

public static ListNode createHeadAddNodeList(int[] dataArray){//頭插法插入數據
ListNode headNode=new ListNode(0);//創建頭結點
headNode.setNext(null);
for(int i=0;i<dataArray.length;i++){
ListNode newNode=new ListNode(dataArray[i]);//賦值數據,創建新節點
newNode.setNext(headNode.getNext());//上一節點的指向賦值給下一節點的指向
headNode.setNext(newNode);//頭結點指向尾部節點

}
return headNode;
}
public static ListNode createEndAddNodeList(int[] dataArray){//頭插法插入數據
ListNode headNode=new ListNode(0);//創建頭結點
headNode.setNext(null);
ListNode pointNode=headNode;//指針節點 一直指向尾節點
for(int i=0;i<dataArray.length;i++){
ListNode newNode=new ListNode(dataArray[i]);
newNode.setNext(pointNode.getNext());
pointNode.setNext(newNode);
pointNode=newNode;
}
return headNode;
}

public static void printHeadAddNodeList(ListNode start){

  if(start!=null){
      System.out.println(start.getData());
      start=start.getNext();
      printHeadAddNodeList(start);

  }

}

public static void deleteNodeByIndex(ListNode startNode,int start,int end){//刪除節點 start值輸入0
if(startNode==null){return;}
if(start<end){//從上往下掃
start++;
startNode=startNode.getNext();
deleteNodeByIndex(startNode,start,end);//遞歸刪除
}else{
startNode.setData(startNode.getNext().getData());
startNode.setNext(startNode.getNext().getNext());
}
}

public static void putNode(ListNode startNode,ListNode dataNode,int start,int end){//參數1開始節點 參數2數據節點

  if(startNode==null){return;}
  if(start<end){
      start++;
      startNode=startNode.getNext();
      putNode(startNode,dataNode,start,end);
  }else{
      dataNode.setNext(startNode.getNext());
      startNode.setNext(dataNode);
  }

}

}

java 模擬單鏈表操作