build a bst as an array using recursion?

Question

    String[] dictionary = new String[dictSize]; //arrray of strings from dictionary
    String[] tree = new String[3*dictSize];       //array of tree

    void makeBST() {

recMakeBST(0, dictionary.length-1);

}//makeBST()

int a=0; void recMakeBST(int low, int high) { if(high-low==0){ return; } else{ int mid=(high-low)/2; tree[a]=dictionary[mid];

a=a+1;

recMakeBST(low, mid-1);

a=a+1;

recMakeBST(mid+1, high); } }