Add 2095 delete the middle node of linked list

typescript/src/2095-delete-the-middle-node.ts

@@ -0,0 +1,53 @@
+// 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
+  }
+}
+
+/**
+ * @param head - list node
+ * @returns list node after middle is deleted
+ *
+ * Problem: https://leetcode.com/problems/delete-the-middle-node-of-a-linked-list
+ */
+export function deleteMiddle(head: ListNode | null): ListNode | null {
+  if (head == null || head.next == null) return null
+
+  let p: ListNode | null = head
+  let middle = findMiddle(head)
+  while (p != null) {
+    if (p.next == middle) {
+      p.next = p.next ? p.next.next : null
+    }
+    p = p.next
+  }
+
+  return head
+}
+
+function findMiddle(head: ListNode | null): ListNode | null {
+  let slow = head
+  let fast = head
+
+  while (fast != null && fast.next != null) {
+    slow = slow ? slow.next : null
+    fast = fast.next.next
+  }
+
+  return slow
+}
+
+if (import.meta.vitest) {
+  const { test, expect } = import.meta.vitest
+  test('test one', () => {
+    expect(
+      deleteMiddle(
+        new ListNode(1, new ListNode(2, new ListNode(3, new ListNode(4))))
+      )
+    ).toStrictEqual(new ListNode(1, new ListNode(2, new ListNode(4))))
+  })
+}