題目： 將一個鏈表進行反轉.
ListNode.java
public class ListNode { int val; ListNode next = null; ListNode(int val) { this.val = val; this.next=null; } }Solution.java
/** * Created by xizwu on 2017/2/16. */public class Solution { public ListNode ReverseList(ListNode head) { if(head==null) return null; ListNode PRe=null; ListNode next=null; while(head !=null){ next=head.next; head.next=pre; pre=head; head=next; } return pre; } public ListNode insert(ListNode head,int val){ //1. 指向 鏈表的末尾 ListNode before=head; if(head==null){ before=new ListNode(val); return before; } while(head.next !=null){ head=head.next; } ListNode myNode=new ListNode(val); head.next=myNode; //2. 添加一個node return before; } public void myprint(ListNode head){ if(head==null){ System.out.println(" The list is empty"); return; } while(head!=null){ System.out.print(head.val+" "); head=head.next; } }}maintest.java
/** * Created by xizwu on 2017/2/16. */public class maintest { public static void main(String[] args) { Solution myso = new Solution(); ListNode myhead = null; ListNode afterResverHead=null; myhead=myso.insert(myhead, 1); myhead=myso.insert(myhead, 2); myhead=myso.insert(myhead, 3); myso.myprint(myhead); afterResverHead=myso.ReverseList(myhead); System.out.println("#################"); myso.myprint(afterResverHead); }}最后的結果：
1 2 3 ################# 3 2 1
新聞熱點
疑難解答
