二分查找（非递归实现和递归实现）详解编程语言

二分查找（非递归实现和递归实现）

public class BinarySearch { 
 
    //非递归实现 
    public static int binarySearch(int array[], int low, int high, int key) { 
        while (low <= high) { 
            int middle = (low + high) / 2; 
            if (array[middle] == key) { 
                return array[middle]; 
            } else if (array[middle] > key) { 
                high = middle - 1; 
            } else { 
                low = middle + 1; 
            } 
        } 
        return -1; 
    } 
 
    //递归实现 
    public static int binarySearch2(int[] array, int low, int high, int key) { 
        if (low > high) { 
            return -1; 
        } else { 
            int middle = (low + high) / 2; 
            if (array[middle] == key) { 
                return array[middle]; 
            } else if (array[middle] > key) { 
                return binarySearch2(array, low, middle - 1, key); 
            } else { 
                return binarySearch2(array, middle + 1, high, key); 
            } 
        } 
    } 
 
    public static void main(String[] args) { 
        int a[] = { 2, 4, 6, 5, 8, 9 }; 
        int reslut = binarySearch2(a, 0, a.length - 1, 1); 
        System.out.println("result : " + reslut); 
    } 
 
}