feat: add typescript solution to lc problem: No.0025.Reverse Nodes in k-Group (#455)

Author: zhaocchen

solution/0000-0099/0025.Reverse Nodes in k-Group/README.md

@@ -155,6 +155,59 @@ 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 reverseKGroup(head: ListNode | null, k: number): ListNode | null {
+    let dummy = new ListNode(0, head);
+    let pre = dummy;
+    // pre->head-> ... ->tail-> next
+    while (head != null) {
+        let tail = pre;
+        for (let i=0; i<k; ++i) {
+            tail = tail.next;
+            if (tail == null) {
+                return dummy.next;
+            }
+        }
+        let t = tail.next;
+        [head, tail] = reverse(head, tail);
+        // set next
+        pre.next = head;
+        tail.next = t;
+        // set new pre and new head
+        pre = tail;
+        head = t;
+    }
+    return dummy.next;
+};
+
+function reverse (head: ListNode, tail: ListNode) {
+    let cur = head;
+    let pre = tail.next;
+    // head -> next -> ... -> tail -> pre
+    while (pre != tail) {
+        let t = cur.next;
+        cur.next = pre;
+        pre = cur;
+        cur = t;
+    }
+    return [tail, head]
+}
+```
+
 ### **Go**
 
 ```go

solution/0000-0099/0025.Reverse Nodes in k-Group/README_EN.md

@@ -142,6 +142,59 @@ 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 reverseKGroup(head: ListNode | null, k: number): ListNode | null {
+    let dummy = new ListNode(0, head);
+    let pre = dummy;
+    // pre->head-> ... ->tail-> next
+    while (head != null) {
+        let tail = pre;
+        for (let i=0; i<k; ++i) {
+            tail = tail.next;
+            if (tail == null) {
+                return dummy.next;
+            }
+        }
+        let t = tail.next;
+        [head, tail] = reverse(head, tail);
+        // set next
+        pre.next = head;
+        tail.next = t;
+        // set new pre and new head
+        pre = tail;
+        head = t;
+    }
+    return dummy.next;
+};
+
+function reverse (head: ListNode, tail: ListNode) {
+    let cur = head;
+    let pre = tail.next;
+    // head -> next -> ... -> tail -> pre
+    while (pre != tail) {
+        let t = cur.next;
+        cur.next = pre;
+        pre = cur;
+        cur = t;
+    }
+    return [tail, head]
+}
+```
+
 ### **Go**
 
 ```go

solution/0000-0099/0025.Reverse Nodes in k-Group/Solution.ts

@@ -0,0 +1,48 @@
+/**
+ * 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 reverseKGroup(head: ListNode | null, k: number): ListNode | null {
+    let dummy = new ListNode(0, head);
+    let pre = dummy;
+    // pre->head-> ... ->tail-> next
+    while (head != null) {
+        let tail = pre;
+        for (let i=0; i<k; ++i) {
+            tail = tail.next;
+            if (tail == null) {
+                return dummy.next;
+            }
+        }
+        let t = tail.next;
+        [head, tail] = reverse(head, tail);
+        // set next
+        pre.next = head;
+        tail.next = t;
+        // set new pre and new head
+        pre = tail;
+        head = t;
+    }
+    return dummy.next;
+};
+
+function reverse (head: ListNode, tail: ListNode) {
+    let cur = head;
+    let pre = tail.next;
+    // head -> next -> ... -> tail -> pre
+    while (pre != tail) {
+        let t = cur.next;
+        cur.next = pre;
+        pre = cur;
+        cur = t;
+    }
+    return [tail, head]
+}