UVA 1597 Searching the Web

Posted 2022-02-06 zaq19970105

题目链接：https://vjudge.net/problem/UVA-1597

题目翻译摘自《算法禁赛入门经典》

题目大意

　　输入 n 篇文章和 m 个请求（n < 100，m ≤ 50000），每个请求都是以下 4 种格式之一。

1. A：查找包含关键字 A 的文章。
2. A AND B：查找同时包含关键字 A 和 B 的文章。
3. A OR B：查找包含关键字 A 或 B 的文章。
4. NOT A：查找不包含关键字 A 的文章。

　　处理询问时，需要对于每篇文章输出证据。前 3 种询问输出所有至少包含一个关键字的行，第 4 种询问输出整篇文章。如果找不到就输出“Sorry, I found nothing.”。并且同一询问，不同文章之间的输出用“----------”分割。类似“middle-class”的单词应该被视为两个单词。关键字只由小写字母组成，查找时忽略大小写。每行不超过 80个字符，一共不超过1500行。

分析

　　考察STL容器的熟练运用。

代码如下

  1 #include <bits/stdc++.h>
  2 using namespace std;
  3  
  4 #define INIT() ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
  5 #define Rep(i,n) for (int i = 0; i < (n); ++i)
  6 #define For(i,s,t) for (int i = (s); i <= (t); ++i)
  7 #define rFor(i,t,s) for (int i = (t); i >= (s); --i)
  8 #define ForLL(i, s, t) for (LL i = LL(s); i <= LL(t); ++i)
  9 #define rForLL(i, t, s) for (LL i = LL(t); i >= LL(s); --i)
 10 #define foreach(i,c) for (__typeof(c.begin()) i = c.begin(); i != c.end(); ++i)
 11 #define rforeach(i,c) for (__typeof(c.rbegin()) i = c.rbegin(); i != c.rend(); ++i)
 12  
 13 #define pr(x) cout << #x << " = " << x << "  "
 14 #define prln(x) cout << #x << " = " << x << endl
 15  
 16 #define LOWBIT(x) ((x)&(-x))
 17  
 18 #define ALL(x) x.begin(),x.end()
 19 #define INS(x) inserter(x,x.begin())
 20 #define UNIQUE(x) x.erase(unique(x.begin(), x.end()), x.end())
 21 #define REMOVE(x, c) x.erase(remove(x.begin(), x.end(), c), x.end()); // 删去 x 中所有 c 
 22 #define TOLOWER(x) transform(x.begin(), x.end(), x.begin(),::tolower);
 23 #define TOUPPER(x) transform(x.begin(), x.end(), x.begin(),::toupper);
 24  
 25 #define ms0(a) memset(a,0,sizeof(a))
 26 #define msI(a) memset(a,inf,sizeof(a))
 27 #define msM(a) memset(a,-1,sizeof(a))
 28 
 29 #define MP make_pair
 30 #define PB push_back
 31 #define ft first
 32 #define sd second
 33  
 34 template<typename T1, typename T2>
 35 istream &operator>>(istream &in, pair<T1, T2> &p) 
 36     in >> p.first >> p.second;
 37     return in;
 38 
 39  
 40 template<typename T>
 41 istream &operator>>(istream &in, vector<T> &v) 
 42     for (auto &x: v)
 43         in >> x;
 44     return in;
 45 
 46  
 47 template<typename T1, typename T2>
 48 ostream &operator<<(ostream &out, const std::pair<T1, T2> &p) 
 49     out << "[" << p.first << ", " << p.second << "]" << "\n";
 50     return out;
 51 
 52 
 53 inline int gc()
 54     static const int BUF = 1e7;
 55     static char buf[BUF], *bg = buf + BUF, *ed = bg;
 56     
 57     if(bg == ed) fread(bg = buf, 1, BUF, stdin);
 58     return *bg++;
 59  
 60 
 61 inline int ri()
 62     int x = 0, f = 1, c = gc();
 63     for(; c<48||c>57; f = c==‘-‘?-1:f, c=gc());
 64     for(; c>47&&c<58; x = x*10 + c - 48, c=gc());
 65     return x*f;
 66 
 67 
 68 template<class T>
 69 inline string toString(T x) 
 70     ostringstream sout;
 71     sout << x;
 72     return sout.str();
 73 
 74 
 75 inline int toInt(string s) 
 76     int v;
 77     istringstream sin(s);
 78     sin >> v;
 79     return v;
 80 
 81 
 82 //min <= aim <= max
 83 template<typename T>
 84 inline bool BETWEEN(const T aim, const T min, const T max) 
 85     return min <= aim && aim <= max;
 86 
 87  
 88 typedef long long LL;
 89 typedef unsigned long long uLL;
 90 typedef pair< double, double > PDD;
 91 typedef pair< int, int > PII;
 92 typedef pair< int, PII > PIPII;
 93 typedef pair< string, int > PSI;
 94 typedef pair< int, PSI > PIPSI;
 95 typedef set< int > SI;
 96 typedef set< PII > SPII;
 97 typedef vector< int > VI;
 98 typedef vector< double > VD;
 99 typedef vector< VI > VVI;
100 typedef vector< SI > VSI;
101 typedef vector< PII > VPII;
102 typedef map< int, int > MII;
103 typedef map< int, string > MIS;
104 typedef map< int, PII > MIPII;
105 typedef map< PII, int > MPIII;
106 typedef map< string, int > MSI;
107 typedef map< string, string > MSS;
108 typedef map< PII, string > MPIIS;
109 typedef map< PII, PII > MPIIPII;
110 typedef multimap< int, int > MMII;
111 typedef multimap< string, int > MMSI;
112 //typedef unordered_map< int, int > uMII;
113 typedef pair< LL, LL > PLL;
114 typedef vector< LL > VL;
115 typedef vector< VL > VVL;
116 typedef priority_queue< int > PQIMax;
117 typedef priority_queue< int, VI, greater< int > > PQIMin;
118 const double EPS = 1e-8;
119 const LL inf = 0x7fffffff;
120 const LL infLL = 0x7fffffffffffffffLL;
121 const LL mod = 1e9 + 7;
122 const int maxN = 1e4 + 7;
123 const LL ONE = 1;
124 const LL evenBits = 0xaaaaaaaaaaaaaaaa;
125 const LL oddBits = 0x5555555555555555;
126 
127 struct Article
128     vector< string > vs;
129     
130     string operator[] (int x) const 
131         return vs[x];
132     
133 ;
134 vector< Article > va;
135 
136 istream& operator >> (istream& in, Article& x)
137     string s;
138     while(getline(cin, s)) 
139         if(!s.size()) continue;
140         if(s == "**********") break;
141         x.vs.PB(s);
142     
143     return in;
144 
145 
146 ostream& operator << (ostream& out, const Article& x)
147     foreach(i, x.vs) out << *i << endl;
148     return out;
149 
150 
151 string tmp; 
152 int N, M;
153 set< string > exc = "the", "a", "to", "and", "or", "not";
154 map< string, set< PII > > dict; // 存文章号和行号的索引 
155 map< string, SI > dicta; // 只存文章号的索引 
156 
157 void build_index(int a_id, const Article &a) 
158     string t;
159     Rep(i, a.vs.size()) 
160         t = a[i];
161         foreach(j, t) if(!isalpha(*j)) *j = ‘ ‘;
162         stringstream sin(t);
163         
164         while(sin >> t) 
165             TOLOWER(t);
166             if(exc.find(t) == exc.end()) 
167                 dict[t].insert(MP(a_id, i));
168                 dicta[t].insert(a_id);
169             
170         
171     
172 
173 
174 int main()
175     //freopen("MyOutput.txt","w",stdout);
176     //freopen("input.txt","r",stdin);
177     //INIT();
178     scanf("%d\n", &N);
179     Rep(i, N) 
180         Article t;
181         cin >> t;
182         build_index(va.size(), t);
183         va.PB(t);
184     
185     
186     scanf("%d\n", &M);
187     Rep(i, M) 
188         getline(cin, tmp);
189         if(tmp.find("NOT") != string::npos) 
190             tmp = tmp.substr(tmp.find(‘ ‘) + 1);
191             int cnt = 0;
192             
193             Rep(i, N) 
194                 if(dicta[tmp].find(i) == dicta[tmp].end()) 
195                     if(cnt++) printf("----------\n");
196                     cout << va[i];
197                 
198             
199             if(!cnt) printf("Sorry, I found nothing.\n");
200          
201         else 
202             set< PII > x;
203             if(tmp.find("AND") != string::npos) 
204                 string a = tmp.substr(0, tmp.find(‘ ‘));
205                 string b = tmp.substr(tmp.find(‘ ‘) + 5);
206                 set< int > sx;
207                 
208                 set_intersection(ALL(dicta[a]), ALL(dicta[b]), INS(sx));
209                 
210                 foreach(i, dict[a]) if(sx.find(i->ft) != sx.end()) x.insert(*i);
211                 foreach(i, dict[b]) if(sx.find(i->ft) != sx.end()) x.insert(*i);
212             
213             else if(tmp.find("OR") != string::npos) 
214                 string a = tmp.substr(0, tmp.find(‘ ‘));
215                 string b = tmp.substr(tmp.find(‘ ‘) + 4);
216                 
217                 set_union(ALL(dict[a]), ALL(dict[b]), INS(x));
218             
219             else x = dict[tmp];
220             
221             int id = x.begin()->ft;
222             foreach(i, x) 
223                 if(i->ft != id) 
224                     printf("----------\n");
225                     id = i->ft;
226                 
227                 cout << va[id][i->sd] << endl;
228              
229             if(x.empty()) printf("Sorry, I found nothing.\n");
230         
231         printf("==========\n");
232     
233     return 0;
234 

View Code