Merge K sorted arrays

Javascript program to merge k sorted // arrays of size n each.

 
    // This function takes an array of 
 
    // arrays as an argument and
 
    // All arrays are assumed to be sorted. 
 
    // It merges them together and prints 
 
    // the final sorted output.
 
    function mergeKArrays(arr , a,  output)
 
    {
 
        var c = 0;
 
 
        // traverse the matrix
 
        for (i = 0; i < a; i++) {
 
            for (j = 0; j < 4; j++)
 
                output = arr[i][j];
 
        }
 
 
        // sort the array
 
        output.sort((a,b)=>a-b);
 
    }
 
 
    // A utility function to print array elements
 
    function printArray(arr , size) {
 
        for (i = 0; i < size; i++)
 
            document.write(arr[i] + " ");
 
    }
 
 
    // Driver program to test above functions
 
     
 
        var arr = [ [ 2, 6, 12, 34 ], 
 
                    [ 1, 9, 20, 1000 ], 
 
                    [ 23, 34, 90, 2000 ] ];
 
        var K = 4;
 
        var N = 3;
 
        var output = Array(N * K).fill(0);
 
 
        mergeKArrays(arr, N, output);
 
 
        document.write("Merged array is ");
 
        printArray(output, N * K);
 

Output Merged array is 1 2 6 9 12 20 23 34 34 90 1000 2000 [Time Complexity:: O(N * K * log (NK))], Since the resulting array is of size NK. Space Complexity: O(N * K), The output array is of size N * K.

Merge K sorted arrays using merging: The process begins with merging arrays into groups of two. After the first merge, there will be K/2 arrays remaining. Again merge arrays in groups, now K/4 arrays will be remaining. This is similar to merge sort. Divide K arrays into two halves containing an equal number of arrays until there are two arrays in a group. This is followed by merging the arrays in a bottom-up