谁能送给我一个2分叉查询方法

Question

谁能送给我一个2分叉查询方法

Answer 1

public class BinarySearch {
/**
* 二分查找算法
*
* @param srcArray 有序数组
* @param key 查找元素
* @return key的数组下标，没找到返回-1
*/

public static void main(String[] args) {
int srcArray[] = {3,5,11,17,21,23,28,30,32,50,64,78,81,95,101};

System.out.println(binSearch(srcArray, 0, srcArray.length - 1, 81));

}

// 二分查找递归实现   
public static int binSearch(int srcArray[], int start, int end, int key) {   
    int mid = (end - start) / 2 + start;   
    if (srcArray[mid] == key) {   
        return mid;   
    }   
    if (start >= end) {   
        return -1;   
    } else if (key > srcArray[mid]) {   
        return binSearch(srcArray, mid + 1, end, key);   
    } else if (key < srcArray[mid]) {   
        return binSearch(srcArray, start, mid - 1, key);   
    }   
    return -1;   
} 

// 二分查找普通循环实现   
public static int binSearch(int srcArray[], int key) {   
    int mid = srcArray.length / 2;   
    if (key == srcArray[mid]) {   
        return mid;   
    }   

    int start = 0;   
    int end = srcArray.length - 1;   
    while (start <= end) {   
        mid = (end - start) / 2 + start;   
        if (key < srcArray[mid]) {   
           end = mid - 1;   
        } else if (key > srcArray[mid]) {   
            start = mid + 1;   
        } else {   
            return mid;   
        }   
    }   
    return -1;   
} 

}