从吃完晚饭开始码代码，看到有个题有思路，便开始坐下来敲代码，发现这个题跟平常做过的题，有相似之处。
但真的敲起来，还真是有困难。
Andy, 8, has a dream - he wants to produce his very own dictionary.
This is not an easy task for him, as the number of words that he knows
is, well, not quite enough. Instead of thinking up all the words
himself, he has a briliant idea. From his bookshelf he would pick one
of his favourite story books, from which he would copy out all the
distinct words. By arranging the words in alphabetical order, he is
done! Of course, it is a really time-consuming job, and this is where
a computer program is helpful.You are asked to write a program that lists all the different words in
the input text. In this problem, a word is defined as a consecutive
sequence of alphabets, in upper and/or lower case. Words with only one
letter are also to be considered. Furthermore, your program must be
CaSe InSeNsItIvE. For example, words like “Apple”, “apple” or “APPLE”
must be considered the same.Input
The input file is a text with no more than 5000 lines. An input
line has at most 200 characters. Input is terminated by EOF.Output
Your output should give a list of different words that appears in the
input text, one in a line. The words should all be in lower case,
sorted in alphabetical order. You can be sure that he number of
distinct words in the text does not exceed 5000.Sample Input
Adventures in Disneyland
Two blondes were going to Disneyland when they came to a fork in the
road. The sign read: “Disneyland Left.”So they went home.
Sample Output
a
adventures
blondes
came
disneyland
fork
going
home
in
left
read
road
sign
so
the
they
to
two
went
were
when
大小写替换tolower()
关于Set容器的小总结。
set容器能够通过平衡二叉树排序，时间复杂度log（n），自动去重（其实无法放入重复元素）
定义：
set<类型> 名称；
操作：
1.有类似字符串的操作方式
2.放入容器 名称.insert(要放入项目)
3.迭代器 set<类型>::iterator 名称 类似指针可以自增自减，不能加减整数
4.通过迭代器
举例如下
set<string>::iterator i;
for(i=a.begin();i!=a.end();++i)
{
cout<<*i<<endl;
}