🟢 Solve problem 23

Author: AF2B

typescript/mergeTwoLists.ts

@@ -0,0 +1,31 @@
+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 mergeTwoLists(list1: ListNode | null, list2: ListNode | null): ListNode | null {
+    if (!list1) return list2;
+    if (!list2) return list1;
+    
+    const tmp = new ListNode();
+    let current = tmp;
+    
+    while (list1 && list2) {
+        if (list1.val <= list2.val) {
+            current.next = list1;
+            list1 = list1.next;
+        } else {
+            current.next = list2;
+            list2 = list2.next;
+        }
+        current = current.next;
+    }
+    
+    current.next = list1 || list2;
+    
+    return tmp.next;
+}