#114 - Binary Search Opportunites

One of my favorite algorithms.

public static Integer search(List<Opportunity> opportunities, Integer target){
    Integer first = 0;
    Integer last = opportunities.size()-1;
    while (first <= last) {
        Integer middle = first + (last - first) / 2;    
        if (target == opportunities[middle].Amount) 
            return middle;
        else if (target < opportunities[middle].Amount) 
            last = middle - 1;
        else
            first = middle + 1;
    }
    return -1;
}