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。
- A：查找包含关键字 A 的文章。
- A AND B：查找同时包含关键字 A 和 B 的文章。
- A OR B：查找包含关键字 A 或 B 的文章。
- 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 }
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