二分查找

public class Main {
public static void main(String[] args) throws Exception {
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
String cout = bufferedReader.readLine();
String[] s = cout.split(" ");
int[] arry = new int[s.length];
for (int i = 0; i < s.length; i++) {
arry[i] = Integer.parseInt(s[i]);
}
myComparator comparator = new myComparator();
int result =  binarySearch(arry,Integer.parseInt(bufferedReader.readLine()),comparator);
System.out.println(result);
}


/**
* 二分法查找。
* @param inputs
* @param key
* @param cp
* @return
*/
public static int binarySearch(int[] inputs, int key,
Comparator<Integer> cp) {
return search(inputs, 0, inputs.length, key, cp);
}


/**
* 二分查找。
* @param inputs 已经从小大拍好序列。
* @param low
* @param high
* @param key
* @param cp
* @return
*/
private static int search(int[] inputs, int low,
int high, int key, Comparator<Integer> cp) {
int index0 = low;
int index1 = high - 1;
while (index0 <= index1) {
int mid = (index0 + index1) >> 1;
int midVal = inputs[mid];
int cmp = cp.compare(midVal, key);
if (cmp < 0)
index0 = index0 + 1 ;
else if (cmp > 0)
index1 = index1 - 1;
else
return mid;//当前返回值为查找数据的下标，midVal为实际数据
// return midVal;//需要根据实际数据类型对返回值类型进行修改
}
return -(index0 + 1);

}

public class myComparator implements Comparator<Integer>{

@Override
public int compare(Integer o1, Integer o2) {
// TODO Auto-generated method stub
return o1>o2 ? 1 : o1 < o2 ? -1 :0;
}
}