feat: add typescript solution to lc problem: No.0234.Palindrome Linked List (#433)

Author: zhaocchen

solution/0200-0299/0234.Palindrome Linked List/README.md

@@ -202,6 +202,50 @@ public class Solution {
 }
 ```
 
+### **TypeScript**
+
+```ts
+/**
+ * Definition for singly-linked list.
+ * class ListNode {
+ *     val: number
+ *     next: ListNode | null
+ *     constructor(val?: number, next?: ListNode | null) {
+ *         this.val = (val===undefined ? 0 : val)
+ *         this.next = (next===undefined ? null : next)
+ *     }
+ * }
+ */
+
+function isPalindrome(head: ListNode | null): boolean {
+    if (head == null || head.next == null) return true;
+    // 快慢指针定位到中点
+    let slow: ListNode = head, fast: ListNode = head.next;
+    while (fast != null && fast.next != null) {
+        slow = slow.next;
+        fast = fast.next.next;
+    }
+    console.log(slow)
+    // 翻转链表
+    let cur: ListNode = slow.next;
+    slow.next = null;
+    let prev: ListNode = null;
+    while (cur != null) {
+        let t: ListNode = cur.next;
+        cur.next = prev;
+        prev = cur;
+        cur = t;
+    }
+    // 判断回文
+    while (prev != null) {
+        if (prev.val != head.val) return false;
+        prev = prev.next;
+        head = head.next;
+    }
+    return true;
+};
+```
+
 ### **...**
 
 ```

solution/0200-0299/0234.Palindrome Linked List/README_EN.md

@@ -203,6 +203,50 @@ public class Solution {
 }
 ```
 
+### **TypeScript**
+
+```ts
+/**
+ * Definition for singly-linked list.
+ * class ListNode {
+ *     val: number
+ *     next: ListNode | null
+ *     constructor(val?: number, next?: ListNode | null) {
+ *         this.val = (val===undefined ? 0 : val)
+ *         this.next = (next===undefined ? null : next)
+ *     }
+ * }
+ */
+
+function isPalindrome(head: ListNode | null): boolean {
+    if (head == null || head.next == null) return true;
+    // 快慢指针定位到中点
+    let slow: ListNode = head, fast: ListNode = head.next;
+    while (fast != null && fast.next != null) {
+        slow = slow.next;
+        fast = fast.next.next;
+    }
+    console.log(slow)
+    // 翻转链表
+    let cur: ListNode = slow.next;
+    slow.next = null;
+    let prev: ListNode = null;
+    while (cur != null) {
+        let t: ListNode = cur.next;
+        cur.next = prev;
+        prev = cur;
+        cur = t;
+    }
+    // 判断回文
+    while (prev != null) {
+        if (prev.val != head.val) return false;
+        prev = prev.next;
+        head = head.next;
+    }
+    return true;
+};
+```
+
 ### **...**
 
 ```

solution/0200-0299/0234.Palindrome Linked List/Solution.ts

@@ -0,0 +1,39 @@
+/**
+ * Definition for singly-linked list.
+ * class ListNode {
+ *     val: number
+ *     next: ListNode | null
+ *     constructor(val?: number, next?: ListNode | null) {
+ *         this.val = (val===undefined ? 0 : val)
+ *         this.next = (next===undefined ? null : next)
+ *     }
+ * }
+ */
+
+ function isPalindrome(head: ListNode | null): boolean {
+    if (head == null || head.next == null) return true;
+    // 快慢指针定位到中点
+    let slow: ListNode = head, fast: ListNode = head.next;
+    while (fast != null && fast.next != null) {
+        slow = slow.next;
+        fast = fast.next.next;
+    }
+    console.log(slow)
+    // 翻转链表
+    let cur: ListNode = slow.next;
+    slow.next = null;
+    let prev: ListNode = null;
+    while (cur != null) {
+        let t: ListNode = cur.next;
+        cur.next = prev;
+        prev = cur;
+        cur = t;
+    }
+    // 判断回文
+    while (prev != null) {
+        if (prev.val != head.val) return false;
+        prev = prev.next;
+        head = head.next;
+    }
+    return true;
+};