2016-04-29 二分查找的面试题

1.面试题

例如： ip计算后的值＝53

文本内容：

1,100,北京
101,1000,上海
1001,3001,广州
...

求ip=53对应的省份

2.代码如下：

#!/usr/bin/python
# coding: utf8

def ip_find(ip):
    f_content="""1,100,北京\n101,1000,上海\n1001,3000,深圳\n3001,10000,广州\n10001,20001,杭州"""
    # print f_content.strip()
    dict1={}
    for i in f_content.split('\n'):
        l1= i.split(',')
        dict1[int(l1[0])] = (int(l1[1]), l1[2])
    # print dict1
    # print dict1[1][1]
    start,end = 0, len(dict1)
    sort(start, end, dict1)

def sort(start, end, dict1):

    if ip>=sorted([i for i in dict1.keys()])[-1]:
        print dict1[sorted([ i for i in dict1.keys()])[-1]][1]
        return 

    len_d = (start+end)/2
    # print 'len_d=%s' % len_d
    # print sorted([i for i in dict1.keys()])
    ip_num_1=sorted([i for i in dict1.keys()])[len_d]
    ip_num_2=sorted([i for i in dict1.keys()])[len_d+1]
    # print "ip_num_1 %s, ip_num_2 %s" % (ip_num_1, ip_num_2)
    if ip_num_1 <= ip < ip_num_2 :
        print dict1[ip_num_1][1]
    elif ip<ip_num_1:
        sort(start, len_d, dict1)
    elif ip >= ip_num_2:
        sort(len_d, end, dict1)

ip=101
ip_find(ip)

结果：
上海
[Finished in 0.0s]