Index Generation

  1 /*
  2     Name: Shangli_Cloud
  3     Copyright: Shangli_Cloud
  4     Author: Shangli_Cloud
  5     Date: 10/10/14 08:15
  6     Description: 
  7     字符串处理题，
  8     在读取过程中，遇到’&‘就PAGe++； 
  9     我们要处理的对象为{}，
 10     对象有  primary,secondary,page属性,所以结构体存储。
 11     当遇到‘{‘是增加entry，遇标记，处理。
 12     排序，三个因素。
 13     我们遇标记处理，定义一个next_token（）标记函数，
 14     定义一个next_char()函数为next_token()函数服务。
 15     注意，当我们遇到某些字符时，需要读取下一个字符，之后再用next_char()的会又会
 16     读取下一个字符，这个字符就跳过了。
 17     所以增加一个变量  lookahead表示是否是有效字符的开始。 
 18 */
 19 #include"iostream"
 20 #include"cstdio"
 21 #include"cstring"
 22 #include"string"
 23 #include"algorithm"
 24 #include"set"
 25 #include"map"
 26 #include"stack"
 27 #include"queue"
 28 #include"vector"
 29 #include"cstdlib"
 30 #include"ctime"
 31 using namespace std;
 32 const int EndOfDocument=-1;
 33 const int EndOfFile=-2;
 34 char ch;
 35 char token;
 36 int page;
 37 bool lookahead;
 38 struct Entry
 39 {
 40     string primary;
 41     string secondary;
 42     int page;
 43     Entry(string p,string s):primary(p),secondary(s),page(::page){};
 44 } ;
 45 vector<Entry>  entry;
 46 int string_compare(const string &s,const string &t)
 47 {
 48     int m=s.length();
 49     int n=t.length();
 50     int k=m<n?m:n;
 51     for(int i=0;i<k;i++)
 52     {
 53         int a=toupper(s[i]);
 54         int b=toupper(t[i]);
 55         if(a!=b)
 56             return a-b;
 57     }
 58     return m==n?0:m<n?-1:1;
 59 }
 60 bool less_than(const Entry &s,const Entry &t)
 61 {
 62     int cmp=string_compare(s.primary,t.primary);
 63     if(cmp<0)
 64         return true;
 65     if(cmp>0)
 66         return false;
 67     cmp=string_compare(s.secondary,t.secondary);
 68     if(cmp<0)
 69         return true;
 70     if(cmp>0)
 71         return false;
 72     return s.page<t.page;
 73 }
 74 inline char next_char()
 75 {
 76     if(lookahead)
 77         lookahead=false;
 78     else
 79         ch=cin.get();
 80     return ch;
 81 }
 82 
 83 
 84 char next_token ()
 85 {
 86     switch (next_char ())
 87     {
 88     case ‘*‘:
 89         token = (next_char () == ‘*‘) ? EndOfFile : EndOfDocument;
 90         break;
 91     case ‘ ‘: 
 92     case ‘\n‘:
 93         next_char ();
 94         if (ch == ‘%‘ || ch == ‘$‘ || ch == ‘}‘)
 95             token = ch;
 96         else {
 97             token = ‘ ‘;
 98             lookahead = true;
 99             break;
100     }
101     case ‘{‘: case ‘%‘: case ‘$‘:
102         token = ch;
103         lookahead = ! isspace (next_char ());
104         break;
105     default:
106         token = ch;
107     }
108     return token;
109 }
110 
111 
112 inline bool is_delimiter(char t)
113 {
114     return t==‘%‘||t==‘$‘||t==‘}‘;
115 }
116 
117 
118 void add_entry ()
119 {
120     string primary, secondary;
121     while (! is_delimiter (next_token ()))
122         primary += token;
123     if (token == ‘%‘)
124     {
125         primary.erase ();  //primary="";
126         while (! is_delimiter (next_token ()))
127             primary += token;          
128     }
129     if (token == ‘$‘)
130         while (! is_delimiter (next_token ()))
131             secondary += token;
132     entry.push_back (Entry (primary, secondary));
133 }
134 
135 
136 int main ()
137 {
138     for (int document = 1; ; ++document)
139     {
140         if (next_token () == EndOfFile) break;
141         cout << "DOCUMENT " << document;
142         page = 1;
143         entry.clear ();
144         entry.push_back (Entry ("", ""));
145         //cout<<"----"<<entry.size()<<endl;
146         do {
147             if (token == ‘&‘)
148                 ++page;
149             else if (token == ‘{‘)
150                 add_entry ();
151         } while (next_token () != EndOfDocument);
152         sort (entry.begin (), entry.end (), less_than);
153         for (int i = 1; i < entry.size(); ++i)
154         {
155             if (entry[i].primary == entry[i-1].primary)
156                 if (entry[i].secondary == entry[i-1].secondary)
157                 {
158                     if (entry[i].page != entry[i-1].page)
159                         cout << ", " << entry[i].page;
160                 }
161                 else
162                     cout<<"\n+ "<<entry[i].secondary<<", "<<entry[i].page; 
163             else
164             {
165                 cout << ‘\n‘ << entry[i].primary;
166                 if (entry[i].secondary == "")
167                     cout << ", " << entry[i].page;
168                 else
169                     cout<<"\n+ "<<entry[i].secondary<<", "<<entry[i].page;
170             }
171         }
172         cout << endl;
173     }
174     return 0;
175 }