python二分法查找 博客分类： python python二分法

下面是一段用Python实现的二分法查找代码

#encoding=utf-8

import sys

def search2(a,m):
    low = 0
    high = len(a) - 1
    while low<=high:
        mid = (low + high)/2
        midval = a[mid]

        if midval<m:
            low = mid + 1
        elif midval>m:
            high = mid-1
        else:
            print mid
            return mid
    print -1
    return -1

if __name__ == "__main__":

    a = [int(i) for i in list(sys.argv[1])]
    m = int(sys.argv[2])
    search2(a,m)

运行测试结果：

shao@ubuntu:~/tmp$ python test_search2.py 123456789 4
3