Code:
import java.util.Scanner;
/** Class KWayMerge **/
public class KWayMerge
{
/** Function to merge arrays **/
private int[] merge(int[][] arr)
{
int K = arr.length;
int N = arr[0].length;
/** array to keep track of non considered positions in subarrays **/
int[] curPos = new int[K];
/** final merged array **/
int[] mergedArray = new int[K * N];
int p = 0;
while (p < K * N)
{
int min = Integer.MAX_VALUE;
int minPos = -1;
/** search for least element **/
for (int i = 0; i < K; i++)
{
if (curPos[i] < N)
{
if (arr[i][curPos[i]] < min)
{
min = arr[i][curPos[i]];
minPos = i;
}
}
}
curPos[minPos]++;
mergedArray[p++] = min;
}
return mergedArray;
}
/** Main method **/
public static void main(String[] args)
{
Scanner scan = new Scanner( System.in );
System.out.println("K Way Merge Test\n");
/** Accept k and n **/
System.out.println("Enter K and N");
int K = scan.nextInt();
int N = scan.nextInt();
int[][] arr = new int[K][N];
/** Accept all elements **/
System.out.println("Enter "+ K +" sorted arrays of length "+ N);
for (int i = 0; i < K; i++)
for (int j = 0; j < N; j++)
arr[i][j] = scan.nextInt();
KWayMerge kwm = new KWayMerge();
int[] mergedArray = kwm.merge(arr);
/** Print merged array **/
System.out.println("\nMerged Array : ");
for (int i = 0; i < mergedArray.length; i++)
System.out.print(mergedArray[i] +" ");
System.out.println();
}
}
Output:
K Way Merge Test
Enter K and N
5 4
Enter 5 sorted arrays of length 4
2 4 6 19
1 20 35 67
3 5 7 11
45 46 47 48
3 9 100 200
Merged Array :
1 2 3 3 4 5 6 7 9 11 19 20 35 45 46 47 48 67 100 200
K Way Merge Test
Enter K and N
4 5
Enter 4 sorted arrays of length 5
2 4 6 19 94
2 8 5 19 63
3 5 7 11 13
1 10 25 50 100
Merged Array :
1 2 2 3 4 5 6 7 8 5 10 11 13 19 19 25 50 63 94 100
K Way Merge Test
Enter K and N
3 10
Enter 3 sorted arrays of length 10
3 6 9 12 15 18 21 24 27 30
2 5 8 11 14 17 20 23 26 29
1 4 7 10 13 16 19 22 25 28
Merged Array :
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
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