v10

test/algorithm/linked_list/206_reverse_list.dart

@@ -0,0 +1,39 @@
+
+void main(){
+  /// 打印 1->9->9->4
+  ListNode listNode = ListNode(1, ListNode(9, ListNode(9,ListNode(4))));
+  print(listNode);
+  ListNode? result = listNode.reverseList(listNode);
+  print(result);
+}
+
+class ListNode {
+  int val;
+  ListNode? next;
+  ListNode([this.val = 0, this.next]);
+
+  @override
+  String toString(){
+    ListNode? cur = this;
+    String result = "";
+    while( cur!=null){
+      result = result +cur.val.toString();
+      cur = cur.next;
+      if(cur!=null){
+        result +='->';
+      }
+    }
+    return result;
+  }
+
+  ListNode? reverseList(ListNode? head) {
+    if (head == null || head.next == null) return head;
+    ListNode? pre = reverseList(head.next);
+    head.next?.next = head;
+    head.next = null;
+    return pre;
+  }
+}
+
+
+