leetcode 23

Author: poorvikaa08

23. Merge k Sorted Lists.cpp

@@ -0,0 +1,36 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode() : val(0), next(nullptr) {}
+ *     ListNode(int x) : val(x), next(nullptr) {}
+ *     ListNode(int x, ListNode *next) : val(x), next(next) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode* mergeKLists(vector<ListNode*>& lists) {
+        ListNode* res = new ListNode(0);
+        ListNode* temp = res;
+
+        priority_queue<int, vector<int>, greater<int>> minHeap;
+
+        for (auto l : lists) {
+            while (l != nullptr) {
+                minHeap.push(l->val);
+                l = l->next;
+            }
+        }
+
+        while (!minHeap.empty()) {
+            int num = minHeap.top();
+            minHeap.pop();
+
+            temp->next = new ListNode(num);
+            temp = temp->next;
+        }
+
+        return res->next;
+    }
+};