二分法查找

    public int search (int[] nums, int target) {
        int indexUp = nums.length-1;
        int indexLower = 0;
        while(indexLower<=indexUp){
            int indexMiddle = (indexUp+indexLower)>>1;
            int currentIndexNum = nums[indexMiddle];
            System.out.println("目标数值:  "+target+"---索引下限："+indexLower+"---当前索引上限："+indexUp+"---索引中位数："+indexMiddle+"---对应数值："+currentIndexNum);
            if(target<currentIndexNum){
                indexUp = indexMiddle-1;
            }
            if(target>currentIndexNum){
                indexLower = indexMiddle+1;
            }
            if(target==currentIndexNum){
                return indexMiddle;
            }
        }
        return -1;
    }