merge k soted arrays code

heap/MergeKSortedArray.java

@@ -0,0 +1,62 @@
+package heap;
+
+import java.util.ArrayList;
+import java.util.PriorityQueue;
+import java.util.Scanner;
+
+public class MergeKSortedArray {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int n = sc.nextInt();
+
+        if (n <= 0) {
+            System.out.println("The number of arrays should be greater than 0.");
+            sc.close();
+            return;
+        }
+
+        int[][] arr = new int[n][n];
+
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < n; j++) {
+                arr[i][j] = sc.nextInt();
+            }
+        }
+
+        mergeKArrays(arr, n);
+
+        sc.close();
+    }
+
+    static ArrayList<Integer> mergeKArrays(int[][] arr, int n) {
+        ArrayList<Integer> res = new ArrayList<>();
+
+        PriorityQueue<Pair> pq = new PriorityQueue<>((a, b) -> a.value - b.value);
+
+        for (int i = 0; i < n; i++)
+            pq.offer(new Pair(arr[i][0], 0, i));
+
+        while (!pq.isEmpty()) {
+            Pair p = pq.poll();
+
+            res.add(p.value);
+
+            if (p.value_index + 1 < n)
+                pq.offer(new Pair(arr[p.arr_index][p.value_index + 1], p.value_index + 1, p.arr_index));
+        }
+
+        return res;
+    }
+}
+
+class Pair {
+    int value;
+    int value_index;
+    int arr_index;
+
+    public Pair(int v, int vi, int ai) {
+        this.value = v;
+        this.arr_index = ai;
+        this.value_index = vi;
+    }
+}