package niu.cheng3;
//二分查找
//注意不要越界。
public class Erfen {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
int[] s1={11,22,33,44,55,66,77,88,99};
int x=Fe(s1,22);
System.out.println("x:"+x);
System.out.println("--------------");
int y=Fe(s1,222);
System.out.println("y:"+y);
}
public static int Fe(int[]s1,int cha){
//最大索引
int da=s1.length-1;
//最小索引
int xiao=0;
//中间索引
int zhong=(da+xiao)/2;
while(s1[zhong]!=cha){
if(s1[zhong]>cha){
da=zhong-1;
}else if(s1[zhong]<cha){
xiao=zhong+1;
}
if(xiao>da){
return -1;
}
zhong=(da+xiao)/2;
}
return zhong;
}
}
//二分查找
//注意不要越界。
public class Erfen {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
int[] s1={11,22,33,44,55,66,77,88,99};
int x=Fe(s1,22);
System.out.println("x:"+x);
System.out.println("--------------");
int y=Fe(s1,222);
System.out.println("y:"+y);
}
public static int Fe(int[]s1,int cha){
//最大索引
int da=s1.length-1;
//最小索引
int xiao=0;
//中间索引
int zhong=(da+xiao)/2;
while(s1[zhong]!=cha){
if(s1[zhong]>cha){
da=zhong-1;
}else if(s1[zhong]<cha){
xiao=zhong+1;
}
if(xiao>da){
return -1;
}
zhong=(da+xiao)/2;
}
return zhong;
}
}