feat: add python and java solutions to leetcode problem: No.0203

Author: yanglbme

README.md

@@ -72,6 +72,7 @@
 
 - [从尾到头打印链表](/lcof/面试题06.%20从尾到头打印链表/README.md)
 - [删除链表的节点](/lcof/面试题18.%20删除链表的节点/README.md)
+- [移除链表元素](/solution/0200-0299/0203.Remove%20Linked%20List%20Elements/README.md)
 - [链表中倒数第 k 个节点](/lcci/02.02.Kth%20Node%20From%20End%20of%20List/README.md)
 - [两两交换链表中的节点](/solution/0000-0099/0024.Swap%20Nodes%20in%20Pairs/README.md)
 - [合并两个有序链表](/solution/0000-0099/0021.Merge%20Two%20Sorted%20Lists/README.md)

README_EN.md

@@ -70,6 +70,7 @@ Complete solutions to [LeetCode](https://leetcode-cn.com/problemset/all/), [LCOF
 ### Linked List
 
 - [Delete Node in a Linked List](/solution/0200-0299/0237.Delete%20Node%20in%20a%20Linked%20List/README_EN.md)
+- [Remove Linked List Elements](/solution/0200-0299/0203.Remove%20Linked%20List%20Elements/README_EN.md)
 - [Kth Node From End of List](/lcci/02.02.Kth%20Node%20From%20End%20of%20List/README_EN.md)
 - [Swap Nodes in Pairs](/solution/0000-0099/0024.Swap%20Nodes%20in%20Pairs/README_EN.md)
 - [Merge Two Sorted Lists](/solution/0000-0099/0021.Merge%20Two%20Sorted%20Lists/README_EN.md)

solution/0200-0299/0203.Remove Linked List Elements/README.md

@@ -24,15 +24,49 @@
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
-
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def removeElements(self, head: ListNode, val: int) -> ListNode:
+        dummy = ListNode(-1, head)
+        pre = dummy
+        while pre and pre.next:
+            if pre.next.val != val:
+                pre = pre.next
+            else:
+                pre.next = pre.next.next
+        return dummy.next
 ```
 
 ### **Java**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
-
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution {
+    public ListNode removeElements(ListNode head, int val) {
+        ListNode dummy = new ListNode(-1, head);
+        ListNode pre = dummy;
+        while (pre != null && pre.next != null) {
+            if (pre.next.val != val) pre = pre.next;
+            else pre.next = pre.next.next;
+        }
+        return dummy.next;
+    }
+}
 ```
 
 ### **...**

solution/0200-0299/0203.Remove Linked List Elements/README_EN.md

@@ -23,13 +23,47 @@
 ### **Python3**
 
 ```python
-
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def removeElements(self, head: ListNode, val: int) -> ListNode:
+        dummy = ListNode(-1, head)
+        pre = dummy
+        while pre and pre.next:
+            if pre.next.val != val:
+                pre = pre.next
+            else:
+                pre.next = pre.next.next
+        return dummy.next
 ```
 
 ### **Java**
 
 ```java
-
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution {
+    public ListNode removeElements(ListNode head, int val) {
+        ListNode dummy = new ListNode(-1, head);
+        ListNode pre = dummy;
+        while (pre != null && pre.next != null) {
+            if (pre.next.val != val) pre = pre.next;
+            else pre.next = pre.next.next;
+        }
+        return dummy.next;
+    }
+}
 ```
 
 ### **...**

solution/0200-0299/0203.Remove Linked List Elements/Solution.java

@@ -3,15 +3,19 @@
  * public class ListNode {
  *     int val;
  *     ListNode next;
- *     ListNode(int x) { val = x; }
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
  * }
  */
 class Solution {
     public ListNode removeElements(ListNode head, int val) {
-        if (head == null) {
-            return null;
+        ListNode dummy = new ListNode(-1, head);
+        ListNode pre = dummy;
+        while (pre != null && pre.next != null) {
+            if (pre.next.val != val) pre = pre.next;
+            else pre.next = pre.next.next;
         }
-        head.next = removeElements(head.next, val);
-        return head.val != val ? head : head.next;
+        return dummy.next;
     }
-}
+}

solution/0200-0299/0203.Remove Linked List Elements/Solution.py

@@ -1,20 +1,15 @@
 # Definition for singly-linked list.
 # class ListNode:
-#     def __init__(self, x):
-#         self.val = x
-#         self.next = None
-
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
 class Solution:
-    def removeElements(self, head, val):
-        """
-        :type head: ListNode
-        :type val: int
-        :rtype: ListNode
-        """
-        if head == None:
-            return None
-        head.next=self.removeElements(head.next,val)
-        if head.val == val:
-            return head.next
-        else:
-            return head
+    def removeElements(self, head: ListNode, val: int) -> ListNode:
+        dummy = ListNode(-1, head)
+        pre = dummy
+        while pre and pre.next:
+            if pre.next.val != val:
+                pre = pre.next
+            else:
+                pre.next = pre.next.next
+        return dummy.next