slt200

Author: jxnu-liguobin

countByAuthors.md

@@ -1,6 +1,6 @@
 #### Order by Join time
 #### 1.Scala
-dreamylost:=> 113
+dreamylost:=> 114
 
 sweeneycai:=> 39
 

scala-leetcode/src/main/scala/io/github/dreamylost/Leetcode_200.scala

@@ -0,0 +1,40 @@
+/* Licensed under Apache-2.0 (C) All Contributors */
+package io.github.dreamylost
+
+/**
+ * 206. 反转链表
+ *
+ * @author 梦境迷离
+ * @since 2021/12/1
+ * @version 1.0
+ */
+object Leetcode_200 {
+
+  def reverseList(head: ListNode): ListNode = {
+    if (head == null || head.next == null) return head
+    val newHead = reverseList(head.next)
+    head.next.next = head
+    head.next = null
+    newHead
+  }
+
+  /**
+   * 500 ms,18.00%
+   * 52.6 MB,94.00%
+   *
+   * @param head
+   * @return
+   */
+  def reverseList2(head: ListNode): ListNode = {
+    var newHead: ListNode = null
+    var curHead = head
+    while (curHead != null) {
+      val tail = curHead.next //保存其余节点，防止丢尾部
+      curHead.next = newHead //断开链，链接新的头节点
+      newHead = curHead // 换头节点，头左移动
+      curHead = tail // 移动旧链
+    }
+    newHead
+  }
+
+}