二分查找算法及时间复杂度

public class Test{
    public static void main(String[] args){
        int[] arr = {1,2,3,4,5,6,7,8,9,10};
        System.out.println(binarySearch(arr, 11));
    }
    private static int binarySearch(int[] arr, int key){
        int low = 0;
        int high = arr.length-1;
        int middle;
        while(low <= high){
            middle = (low+high)/2;
            if(arr[middle] > key){
                high = middle-1;
            }else if(arr[middle] < key){
                low = middle+1;
            }else{
                return middle;
            }
        }
        return -1;
    }
}

时间复杂度：O（log2n）