CareerCup

Set<Integer> intersection(int a[], int[] b) {

		Set<Integer> fir_set = new HashSet<Integer>();
		Set<Integer> intersection = new HashSet<Integer>();
		
		for (int i : a) {
			if (fir_set.contains(i)) {
				continue;
			}
			fir_set.add(i);
		}

		for (int j : b) {
			if (fir_set.contains(j))
			{
				intersection.add(j);
			}
			
		}
		return intersection;
	}

This uses Set data structure.

void interset(int * arr1, int sz1, int * arr2, int sz2) 
{
  if (!((sz1 > 0) && (sz2 > 0))) return;
  
  int *p1 = arr1;
  int *p2 = arr2;
  
  while ( (p1 <= (arr1+sz1)) && (p2 <= (arr2+sz2)))
  {
    if (*p1 == *p2) {
      printf("%d ", *p1);
      p1++; 
      p2++;
    } else if (*p1 > *p2) {
      p2++;
    } else {
      p1++;
    }
  }
}

Do a merge sort?

while(i<n && j<m){
if(a[i] < b[j]) i++;
else if(b[j] < a[i]) j++;
else {System.out.println(a[i]); i++; j++;}
}

@hunt: your answer is incomplete, though you're trying to find the matching elements/intersection.

@morpheus: question is not clear
#1 . does the intersection part appears contiguously? or partly here partly there
give a proper example.

hunt's answer seems to on the correct lines.
interviewer added later that no dupes should be printed.
also asked me to list the (unit) testcases for the function.

Use a HashMap

public void printIndex(int[] A, int[] B){
	int a = 0;
	int b = 0;
	int lengthA = A.length;
	int lengthB = b.length;
	while(a < lengthA && b <lengthB) {
		if (A[a] == B[b]) {
			System.out.println(A[a]);
			a++;
			b++;
		}
		else if (A[a] < B[b]) {
			a++;
		}
		else {
			b++;
		}
	}
}

public void printIndex(int[] A, int[] B){
	int a = 0;
	int b = 0;
	int lengthA = A.length;
	int lengthB = b.length;
	while(a < lengthA && b <lengthB) {
		if (A[a] == B[b]) {
			System.out.println(A[a]);
			a++;
			b++;
		}
		else if (A[a] < B[b]) {
			a++;
		}
		else {
			b++;
		}
	}
}

For solving the above algorithm we will need to do a merge sort operation, and we will compare the elements of the two arrays if the first element of the first array is less than the first element of the second array then increment the index of the first array because there may the next element which intersects with the first array and similarly increment the index of the second array when the element of the second array is less than the first array and when both the array elements are equal then print the element and increment both the array indexes.