From b19af65b79a1bb4fd64dc7523a5fa60867b29b0e Mon Sep 17 00:00:00 2001
From: weikunkun <kongwiki@163.com>
Date: Wed, 12 May 2021 21:07:20 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A00203.=E7=A7=BB=E9=99=A4?=
 =?UTF-8?q?=E9=93=BE=E8=A1=A8=E5=85=83=E7=B4=A0=20Java=E7=89=88=E6=9C=AC?=
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---
 problems/0203.移除链表元素.md | 58 ++++++++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/problems/0203.移除链表元素.md b/problems/0203.移除链表元素.md
index e6667091..9fca1ee0 100644
--- a/problems/0203.移除链表元素.md
+++ b/problems/0203.移除链表元素.md
@@ -138,7 +138,63 @@ public:
 
 
 Java：
-
+```java
+/**
+ * 添加虚节点方式
+ * 时间复杂度 O(n)
+ * 空间复杂度 O(1)
+ * @param head
+ * @param val
+ * @return
+ */
+public ListNode removeElements(ListNode head, int val) {
+    if (head == null) {
+        return head;
+    }
+    // 因为删除可能涉及到头节点，所以设置dummy节点，统一操作
+    ListNode dummy = new ListNode(-1, head);
+    ListNode pre = dummy;
+    ListNode cur = head;
+    while (cur != null) {
+        if (cur.val == val) {
+            pre.next = cur.next;
+        } else {
+            pre = cur;
+        }
+        cur = cur.next;
+    }
+    return dummy.next;
+}
+/**
+ * 不添加虚拟节点方式
+ * 时间复杂度 O(n)
+ * 空间复杂度 O(1)
+ * @param head
+ * @param val
+ * @return
+ */
+public ListNode removeElements(ListNode head, int val) {
+    while (head != null && head.val == val) {
+        head = head.next;
+    }
+    // 已经为null，提前退出
+    if (head == null) {
+        return head;
+    }
+    // 已确定当前head.val != val
+    ListNode pre = head;
+    ListNode cur = head.next;
+    while (cur != null) {
+        if (cur.val == val) {
+            pre.next = cur.next;
+        } else {
+            pre = cur;
+        }
+        cur = cur.next;
+    }
+    return head;
+}
+```
 
 Python：