http://togetter.com/li/669617 の解答

ticket.py

#!/usr/bin/env python
# coding:utf-8

import re
import datetime

class Ticket:
    def __init__(self, name, start, end):
        self.name = name
        self.start = start
        self.end = end

# 2/29があったので、閏年にしておく
year = 2016

# ファイル読み込み
tickets_temp = []
for line in open('tickets.txt', 'r'):
    tickets_temp.append(re.split('[ -]', line.rstrip("\r\n")))

tickets = []
for item in tickets_temp:
    arr1 = item[1].split("/")
    arr2 = item[2].split("/")
    s = datetime.date(year, int(arr1[0]), int(arr1[1]))
    e = datetime.date(year, int(arr2[0]), int(arr2[1]))
    tickets.append( Ticket(item[0], s, e) )

# 終わりの日付でソート
tickets.sort( key = lambda item: item.end)

# 解答となるプランを作る
plan = [tickets[0]]
for item in tickets:
    if plan[-1].end < item.start:
        plan.append(item)

for item in plan:
    print "%s: %s - %s" % (item.name, item.start, item.end)

print
print "number of tickets: %d" % len(plan)

print
print "answer:"
print len(plan),
for item in sorted(plan):
    print item.name,