A recursive algorithm to find two integers in an array that sums to a given integer

Question

I need an algorithm to determine if an array contains two elements that sum to a given integer.

The array is sorted.

The algorithm should be recursiv

Answer 1

Normally I'd use a Map, but since one of the requirements is to use a linear data structure, I think that's excluded, so I'd go about using a boolean array.

public boolean hasSum( int[] numbers, int target )
{
    boolean[] hits = new boolean[ target + 1 ];
    return hasSumRecursive( 0, numbers, target, hits );
}

public boolean hasSumRecursive( int index, int[] numbers, int target, boolean[] hits )
{
    ...
}

Hopefully this is a good enough hint.