JavaʵÏÖ ¶þ·Ö²éÕÒ

/**
 * ʹÓöþ·Ö²éÕҵķ½Ê½²éѯָ¶¨µÄÖµ
 * @author ZhangYu
 * @data 2010-01-23
 */
public class BinSearch {
/**
* ÓõݹéʵÏÖ¶þ·Ö²éÕÒ
* @param data -±»²éÕÒµÄÊý×é
* @param value -Òª²éÕÒµÄÖµ
* @param left -²éÕÒ·¶Î§µÄ×îСֵ
* @param right -²éÕÒ·¶Î§µÄ×î´óÖµ
* @return ·µ»Ø²éÕÒµÄϱ꣬ûÓвéÕÒµÄÖµ·µ»Ø-1
*/
public int search(int[] data ,int value ,int left ,int right){
int mid = (right-left)/2 + left; //µ±Ç°±È½ÏÖµµÄϱê
/*
* Í˳öÌõ¼þ
*/
if(left > right){
return -1;
}
if(value == data[mid]){
return mid;
}else if(value > data[mid]){
return search(data ,value ,mid +1 ,right); //ÉèÖÃеÄ×îС·¶Î§
}else if(value < data[mid]){
return search(data, value, left, mid - 1); //ÉèÖÃеÄ×î´ó·¶Î§
}
return -1;
}

/**
* ÓÐÑ­»·µÄ·½Ê½ÊµÏÖ¶þ·Ö²éÕÒ
* @param data -±»²éÕҵĶÔÏñ
* @param value -Òª²éÕÒµÄÖµ
* @return ·µ»Ø²éÕÒµÄϱ꣬ûÓвéÕÒµÄÖµ·µ»Ø-1
*/
public int search(int []data ,int value){
int left = 0; //²éÕÒ·¶Î§µÄ×îСֵ
int right = data.length - 1; //²éÕÒ·¶Î§µÄ×î´óÖµ
while(left <= right){
int mid = (right-left)/2 + left; //µ±Ç°±È½ÏÖµµÄϱê
if(value == data[mid]){
return mid;
}else if(value > data[mid]){
left = mid+1; //ÉèÖÃеÄ×îС·¶Î§
}else if(value < data[mid]){
right = mid-1; //ÉèÖÃеÄ×î´ó·¶Î§
}
}
return -1;
}

public static void main(String []args){
BinSearch bs = new BinSearch();
int [] data = {1,5,7,9,15,16,20,25,28,30,38};
System.out.println(bs.search(data, 5, 0, data.length-1));
System.out.println(bs.search(data, 7));
}
}