二分查找

package BinarySearch;

public class BinarySearch {

    /**
     * @param args
     */
    public static void main(String[] args) {
        int[] sort={1,3,4,5,6,8,9};
        int index=binarySearch(sort,9);
        
        System.out.println(index);

    }

    private static int binarySearch(int[] sort, int data) {
        if(data<sort[0] || data>sort[sort.length-1]){
            return -1;
        }
        int begin=0;
        int end=sort.length;
        int mid=(begin+end)/2;
        while(begin<=end){
            mid=(begin+end)/2;
            if(data>sort[mid] ){
                begin=mid++;
            }else if(data<sort[mid]){
                end=mid--;
            }else{
                return mid;
            }
        }
        return -1;
    }

}