Add Elements of the Second Array into the First

Add Elements of the Second Array into the First
Given two sorted arrays, A and B. Write a method merging the elements of B into A in sorted order. Assume A has a large enough buffer at the end to hold all of B's elements.

you don't need to copy the contents of A after running out of elements in B. They are already in

place.

void merge(int[] a, int[] b, int lastA, int lastB) {
        int indexA = lastA - 1; /* Index of last element in array a*/
        int indexB = lastB - 1; /* Index of last element in array b */
        int indexMerged = lastB + lastA - 1; /* end of merged array*/

        /* Merge a and b, starting from the last element in each*/
        while (indexB >= 0) {
                /* end of a is > than end of b */
                if (indexA >= 0 && a[indexA] > b[indexB]) {
                        a[indexMerged] = a[indexA]; // copy element
                        indexA- -;
                } else {
                        a[indexMerged] b[indexB]; // copy element
                        indexB--;
                }
                indexMerged--; // move indices
        }
}

Suppose we want to merge two arrays a1 and a2. a1 has n elements and has space for n + m elements. a2 has m elements. Suppose arrays are sorted in ascendant order.

int* merge(int* a1, int n, int* a2, int m)

{

int ind = m + n - 1; // fill resulting array from the end

m = m-1; n = n-1;

while (m >= 0 && n >= 0)

{

if (a1[n] >= a2[m])

{

a1[ind] = a1[n];

--n;

}

else

{

a1[ind] = a2[m];

--m;

}

--ind;

}

if (m >= 0)

memcpy(a1, a2, (m + 1) * sizeof(int));

return a1;

}

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