Solution for 154 Merge K-Sorted Arrays

src/com/company/Heaps/MergeKSorted.java

@@ -0,0 +1,58 @@
+package Heap;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+import java.util.PriorityQueue;
+
+public class KWayMerge {
+    public static void main(String[] args) {
+        List<List<Integer>> lists = Arrays.asList(Arrays.asList(10, 15, 20, 30), Arrays.asList(2, 5, 8, 14, 24),
+                Arrays.asList(0, 11, 60, 90));
+        List<Integer> result = merge(lists);
+        System.out.println(result);
+    }
+
+    private static List<Integer> merge(List<List<Integer>> lists) {
+        //logic
+        List<Integer> outPut = new ArrayList<>();
+        // triplet of (value, array_index,value_index)
+        PriorityQueue<Element> pq = new PriorityQueue<>(Comparator.comparingInt(o -> o.value));
+
+        for (int i = 0; i < lists.size(); i++) {
+            Element e = new Element(lists.get(i).get(0), 0, i);
+            pq.offer(e);
+        }
+
+        while (!pq.isEmpty()) {
+            Element peek = pq.peek();
+            pq.remove();
+
+            int elem = peek.value;
+            int arrayIndex = peek.row;
+            int elemIndex = peek.idx;
+
+            outPut.add(elem);
+
+            if (elemIndex + 1 < lists.get(arrayIndex).size()) {
+                pq.offer(new Element(lists.get(arrayIndex).get(elemIndex + 1), elemIndex + 1, arrayIndex));
+            }
+        }
+
+        return outPut;
+    }
+
+}
+
+class Element {
+    int value;
+    int idx;
+    int row;
+
+    public Element(int value, int idx, int row) {
+        this.value = value;
+        this.idx = idx;
+        this.row = row;
+    }
+}