二分法查找

public class BinarySearch {

//退出条件是找到对应的值或者start >= end值。public static int search(int searchNo,int[] arr,int start,int end){int mid = (start+end)/2;System.out.println("start:"+start+" end:"+end);if(start >= end){return -1;}if(arr[mid] == searchNo){return mid;}else if(arr[mid] > searchNo){return search(searchNo,arr,start,mid-1);}else{return search(searchNo,arr,mid+1,end);}}

public static void main(String[] args) {int[] arr = {1,4,6,11,45,67,89,123,145};System.out.println(BinarySearch.search(456,arr,0,8)+"");}

}