二分法

package ArrayDemo;import java.util.Arrays;public class ArrayDemo01 {/* * 二分法查找(有序数组中进行查找) * 输入与输出 */public int getArgs(int t,int k[]){int low=0;int high=k.length-1;while(low<=high){//分到最后最小索引<=最大索引int mid=(low+high)/2;//二分中点=数组左边界+(右边界-左边界)/2  //整数类型默认取下整 if(k[mid]>t){//[low,mid-1]high=mid-1;//最中间数已经比较，可以不用比较}else if(k[mid]<t){low=mid+1;//因为区间变成[mid+1,high]}else{returnmid ;}}return -1;}public static void main(String[] args) {int j[]={1,2,3,4,5,6,7};int x[]=Arrays.copyOf(j, 3);//数组名字加新数组长度for (int i = 0; i < x.length; i++) {System.out.println(x[i]);//1,2,3}ArrayDemo01 arrayDemo01=new ArrayDemo01();System.out.println(arrayDemo01.getArgs(3, j));//预期结果为2System.out.print(Arrays.binarySearch(j, 3));//2}}