merge k sorted lists solution

Author: hyer0705

merge-k-sorted-lists/hyer0705.ts

@@ -0,0 +1,37 @@
+/**
+ * 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 mergeKLists(lists: Array<ListNode | null>): ListNode | null {
+  if (!lists || lists.length === 0) return null;
+
+  const minHeap = new PriorityQueue((a: ListNode, b: ListNode) => a.val - b.val);
+
+  for (const node of lists) {
+    if (node) minHeap.enqueue(node);
+  }
+
+  const dummyHead = new ListNode();
+  let current = dummyHead;
+
+  while (!minHeap.isEmpty()) {
+    const minimumElement = minHeap.dequeue();
+
+    current.next = minimumElement;
+    current = current.next;
+
+    if (minimumElement.next) {
+      minHeap.enqueue(minimumElement.next);
+    }
+  }
+
+  return dummyHead.next;
+}