/**

     * * 二分查找算法 * *

     *

     * @param srcArray 有序数组 *

     * @param target 查找元素 *

     * @return srcArray数组下标，没找到返回-1

     */

   public int binarySearch(int[] srcArray, int target){

        int left = 0;

        int right = srcArray.length - 1;

        while(left <= right) {

            int mid = left + (right - left)/2;

            if(srcArray[mid] == target) {

                return mid;

            }

            else if(srcArray[mid] > target) {

                right = mid - 1;

            }

            else {

                left = mid + 1;

            }

        }

        return -1;

   }