Day10_数组（下）

二分法排序

使用前提：数组为有序数组

public class BinarySearch {
    public static void main(String[] args) {
        int[] arr={1,2,3,4,5,6,7,8,9};
        int index=binarySearch(arr,7,0,arr.length-1);
        System.out.println(index);
    }
    public static int binarySearch(int[] arr,int term,int low,int high){
        int index=-1;
        int mid=(low+high)/2;
        int guess=arr[mid];
        if(low>high){
            return index;
        }else if(guess==term){
            return mid;
        }else if(guess>term){
            return binarySearch(arr,term,low,mid-1);
        }else {
            return binarySearch(arr,term,mid+1,high);
        }
    }
}
public clas