Median of two sorted arrays of same size (두 정렬된 배열의 중간값)

// A Simple Merge based O(n) solution to find median of
// two sorted arrays
 
/* This function returns median of ar1[] and ar2[].
Assumptions in this function:
Both ar1[] and ar2[] are sorted arrays
Both have n elements */
function getMedian(ar1, ar2, n)
{
    var i = 0; /* Current index of i/p array ar1[] */
    var j = 0; /* Current index of i/p array ar2[] */
    var count;
    var m1 = -1, m2 = -1;
 
    /* Since there are 2n elements, median will be average
    of elements at index n-1 and n in the array obtained after
    merging ar1 and ar2 */
    for (count = 0; count <= n; count++)
    {
        /*Below is to handle case where all elements of ar1[] are
        smaller than smallest(or first) element of ar2[]*/
        if (i == n)
        {
            m1 = m2;
            m2 = ar2[0];
            break;
        }
 
        /*Below is to handle case where all elements of ar2[] are
        smaller than smallest(or first) element of ar1[]*/
        else if (j == n)
        {
            m1 = m2;
            m2 = ar1[0];
            break;
        }
        /* equals sign because if two
            arrays have some common elements */
        if (ar1[i] <= ar2[j])
        {
            m1 = m2; /* Store the prev median */
            m2 = ar1[i];
            i++;
        }
        else
        {
            m1 = m2; /* Store the prev median */
            m2 = ar2[j];
            j++;
        }
    }
 
    return (m1 + m2)/2;
}
 
/* Driver program to test above function */
var ar1 = [1, 12, 15, 26, 38];
var ar2 = [2, 13, 17, 30, 45];
var n1 = ar1.length;
var n2 = ar2.length;
if (n1 == n2)
    document.write("Median is "+ getMedian(ar1, ar2, n1));
else
    document.write("Doesn't work for arrays of unequal size");