/**

      * 二分查找

      * @param a

      * @param n

      * @param value

      * @return

      * @date 2016-10-8

      * @author shaobn

      */

         public static int binaryFind(int[] a,int n,int value){

             int lowNum = 0;

             int highNum = n-1;

             while(lowNum<=highNum){

                 int midNum = (lowNum+highNum)/2;

                 if(a[midNum]==value){

                     return midNum;

                 }else if (a[midNum]>value) {

                     highNum = midNum-1;

                 }else if (a[midNum]<value) {

                     lowNum = midNum+1;

                 }

             }

             return -1;

         }