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saikatkar · Jan 4, 2022 · 0a143dc · 0a143dc
1 parent 1326a18
commit 0a143dc
Showing 1 changed file with 40 additions and 0 deletions.
diff --git a/23-merge-k-sorted-lists/23-merge-k-sorted-lists.java b/23-merge-k-sorted-lists/23-merge-k-sorted-lists.java
@@ -0,0 +1,40 @@
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution {
+    public ListNode mergeKLists(ListNode[] lists) {
+        Comparator<ListNode> cmp;
+        cmp = new Comparator<ListNode>() {  
+        @Override
+        public int compare(ListNode o1, ListNode o2) {
+            // TODO Auto-generated method stub
+            return o1.val-o2.val;
+        }
+        };
+        Queue<ListNode> pq = new PriorityQueue<>(cmp);
+        ListNode mergedHead = new ListNode();
+        ListNode result = mergedHead;
+        for (ListNode ln : lists) {
+            if(ln != null) {
+                pq.add(ln);  
+            }
+        }
+        while (!pq.isEmpty()) {
+            ListNode min = pq.poll();
+            mergedHead.next = min;
+            mergedHead = mergedHead.next;
+            if (min.next != null) {
+                min = min.next;
+                pq.add(min);
+            }
+        }
+        return result.next;
+    }
+}