java实现二分查找

 /**
      * 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;
         }