UVA 230 Borrowers （STL 行读入的处理 重载小于号）

题意：

输入若干书籍和作者名字，然后先按作者名字升序排列，再按标题升序排列，然后会有3种指令，BORROW,RETURN, SHELVE。

BORROW 和 RETURN 都会带有一个书名在后面，如：

BORROW "The Canterbury Tales"
RETURN "The Canterbury Tales"

当遇到SHELVE指令，输出已还但没上架的书排序后（规则同上）依次插入书架的序列。

用例：

输入：

"The Canterbury Tales" by Chaucer, G.
"Algorithms" by Sedgewick, R.
"The C Programming Language" by Kernighan, B. and Ritchie, D.
END
BORROW "The Canterbury Tales"
RETURN "The Canterbury Tales"
BORROW "The C Programming Language"
RETURN "The C Programming Language"
SHELVE
BORROW "Algorithms"
RETURN "Algorithms"
SHELVE
END

输出：

Put "The Canterbury Tales" first
Put "The C Programming Language" after "The Canterbury Tales"
END
Put "Algorithms" after "The C Programming Language"
END

分析：

这题的读入有点麻烦，我的处理是使用getline， 然后将 “ 号变成空格 将空格变成“#”（ASCII差距不大）， 再用stringsteam输入到string中，最后输出再将“#”转换为“ ”。

网上的方法是使用string.substr()截取,用string.find()去寻找位置， 我截取这种方法更好（stringsteam很慢）。

用map<string,int>将string映射到书架位置上面，用一个bool去标记这个位置有没被拿走，注意return后不能直接把书放回去，要标记，等收到SHELVE指令再排序放书。

 #include <cstdio>
 #include <cstring>
 #include <vector>
 #include <map>
 #include <string>
 #include <iostream>
 #include <set>
 #include <sstream>
 #include <algorithm>
 using namespace std;
 struct B
 {
     string name;
     string author;
     B(){}
     B(const string& _name,const string& _author):
         name(_name),author(_author){}
     friend bool operator < (const B a,const B b)
     {
         if(a.author < b.author) return true;
         else
         {
             if(a.author == b.author)
             {
                 if(a.name < b.name)
                     return true;
                 else return false;
             }
             else return false;
         }
     }
 };
 struct A
 {
     int a;
     int b;
     A(){}
     A(int _a, int _b):
         a(_a), b(_b){}
 //    a after b of a is the first(b=-1);
 };
 typedef set<B> :: iterator sIT;
 typedef vector<B> :: iterator vIT;
 typedef vector<A> :: iterator aIT;
 typedef vector<int> :: iterator IT;
 string trans(const string& a)
 {
     string t = a;
     for(int i = ; i < t.size(); i++)
     {
         if(t[i] == '#') t[i] = ' ';
     }
     return t;
 }
 int main()
 {
     ios::sync_with_stdio(false);
     #if LOCAL
     freopen("1.txt","r",stdin);
     freopen("2.txt","w",stdout);
     #endif // LOCAL
     string s;
     vector<B> book;
     bool lend[];
     vector<A> ans;
     fill(lend, lend+,);
     map<string,int> id;
     vector<int> ret;
     while(getline(cin,s))
     {
         for(int i = ; i < s.size(); i++)
         {
             if(s[i] == '"') s[i] = ' ';
             else if(s[i] == ' ') s[i] = '#';
         }
         stringstream ss(s);
         string tname, tauthor;
         if(!(ss>>tname>>tauthor)) break;
         book.push_back(B(tname,tauthor));
     }
     sort(book.begin(), book.end());
     int cnt = ;
     for(vIT it = book.begin(); it != book.end(); it++)
     {
         id[(*it).name] = cnt++;
     }
     string op;
     while(cin>>op)
     {
         if(op=="END") break;
         if(op == "SHELVE")
         {
             sort(ret.begin(), ret.end());
             for(IT it = ret.begin(); it != ret.end(); it++)
             {
                 lend[*it] = ;
                 int c = (*it) -;
                 for(; c >=  && lend[c] == ; c--);
                 ans.push_back(A(*it,c));
             }
             ret.clear();
             for(aIT it = ans.begin(); it != ans.end(); it++)
             {
                 if((*it).b != -)
                 {
                     cout<<"Put \""<< trans(book[(*it).a].name) << "\" after \"" << trans(book[(*it).b].name) << "\"\n";

                 }
                 else
                 {
                     cout<<"Put \""<<trans(book[(*it).a].name)<< "\" first"<<"\n";

                 }
             }
             ans.clear();
             cout<<"END\n";
             continue;
         }
         cin.ignore();
         string b;
         getline(cin,b);
         for(int i = ; i < b.size(); i++)
         {
             if(b[i] == '"') b[i] = ' ';
             else if(b[i] == ' ') b[i] = '#';
         }
         stringstream ss(b);
         ss>>b;
         if(op== "BORROW")
         {
             lend[id[b]] = ;
         }
         else if(op == "RETURN")
         {

             ret.push_back(id[b]);
         }
     }

     return ;
 }