python实现二分查找

# coding:utf8
__author__ = 'bluesli'




def binary_search(data_source,find_n):
    mid = int(len(data_source)/2)#这里直接通过长度获取中间值，无需再添加变量low，height，middle这些变量；
    if len(data_source)>=1:  #利用切片后的长度作为结束标志

        if data_source[mid] > find_n:
            print('data in left')
            print(data_source[:mid])
            binary_search(data_source[:mid],find_n)
        elif data_source[mid]<find_n:
            print('data is in right')
            print(data_source[mid:])
            binary_search(data_source[mid:],find_n) #利用切片可以很快的获取值所在的范围的序列；然后直接获取长度，利用长度再次找到中间位置；
        else:
            print('find it',data_source[mid])
            print(mid)
    else:
        print('cannot find')




if __name__ == '__main__':
    data = list(range(1, 10, 3))
    print(data)
    binary_search(data,7)

c 语言实现二分查找：相比于python空间复杂读高了；

int BinySerch(int *arr, int x, int lengh)//设计参数，由于是整形数组，所以我们必须传递他
{                                        //长度否则数组传参时会发生降级
int left = 0, right = lengh - 1;
int mid ;
while (left <= right)
{
mid = left + (right - left) / 2;
if (x < arr[mid])
{
right = mid - 1;
}
else if (x > arr[mid])
{
left = mid + 1;
}
else
{
return mid;
}
}
return -1;
}
int main()//测试用例
{
int x = 0;
int arr[11] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
int lengh = sizeof(arr) / sizeof(arr[0]);
for (int i = 0; i < 12; i++)
{
printf("%d ",BinySerch(arr, i, lengh));
}
system("pause");
return 0;
}