UVA 1597 Searching the Web

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

#include <bits/stdc++.h>
using namespace std;
 
#define INIT() ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define Rep(i,n) for (int i = 0; i < (n); ++i)
#define For(i,s,t) for (int i = (s); i <= (t); ++i)
#define rFor(i,t,s) for (int i = (t); i >= (s); --i)
#define ForLL(i, s, t) for (LL i = LL(s); i <= LL(t); ++i)
#define rForLL(i, t, s) for (LL i = LL(t); i >= LL(s); --i)
#define foreach(i,c) for (__typeof(c.begin()) i = c.begin(); i != c.end(); ++i)
#define rforeach(i,c) for (__typeof(c.rbegin()) i = c.rbegin(); i != c.rend(); ++i)
 
#define pr(x) cout << #x << " = " << x << "  "
#define prln(x) cout << #x << " = " << x << endl
 
#define LOWBIT(x) ((x)&(-x))
 
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())
#define UNIQUE(x) x.erase(unique(x.begin(), x.end()), x.end())
#define REMOVE(x, c) x.erase(remove(x.begin(), x.end(), c), x.end()); // 删去 x 中所有 c 
#define TOLOWER(x) transform(x.begin(), x.end(), x.begin(),::tolower);
#define TOUPPER(x) transform(x.begin(), x.end(), x.begin(),::toupper);
 
#define ms0(a) memset(a,0,sizeof(a))
#define msI(a) memset(a,inf,sizeof(a))
#define msM(a) memset(a,-1,sizeof(a))

#define MP make_pair
#define PB push_back
#define ft first
#define sd second
 
template<typename T1, typename T2>
istream &operator>>(istream &in, pair<T1, T2> &p) {
    in >> p.first >> p.second;
    return in;
}
 
template<typename T>
istream &operator>>(istream &in, vector<T> &v) {
    for (auto &x: v)
        in >> x;
    return in;
}
 
template<typename T1, typename T2>
ostream &operator<<(ostream &out, const std::pair<T1, T2> &p) {
    out << "[" << p.first << ", " << p.second << "]" << "
";
    return out;
}

inline int gc(){
    static const int BUF = 1e7;
    static char buf[BUF], *bg = buf + BUF, *ed = bg;
    
    if(bg == ed) fread(bg = buf, 1, BUF, stdin);
    return *bg++;
} 

inline int ri(){
    int x = 0, f = 1, c = gc();
    for(; c<48||c>57; f = c=='-'?-1:f, c=gc());
    for(; c>47&&c<58; x = x*10 + c - 48, c=gc());
    return x*f;
}

template<class T>
inline string toString(T x) {
    ostringstream sout;
    sout << x;
    return sout.str();
}

inline int toInt(string s) {
    int v;
    istringstream sin(s);
    sin >> v;
    return v;
}

//min <= aim <= max
template<typename T>
inline bool BETWEEN(const T aim, const T min, const T max) {
    return min <= aim && aim <= max;
}
 
typedef long long LL;
typedef unsigned long long uLL;
typedef pair< double, double > PDD;
typedef pair< int, int > PII;
typedef pair< int, PII > PIPII;
typedef pair< string, int > PSI;
typedef pair< int, PSI > PIPSI;
typedef set< int > SI;
typedef set< PII > SPII;
typedef vector< int > VI;
typedef vector< double > VD;
typedef vector< VI > VVI;
typedef vector< SI > VSI;
typedef vector< PII > VPII;
typedef map< int, int > MII;
typedef map< int, string > MIS;
typedef map< int, PII > MIPII;
typedef map< PII, int > MPIII;
typedef map< string, int > MSI;
typedef map< string, string > MSS;
typedef map< PII, string > MPIIS;
typedef map< PII, PII > MPIIPII;
typedef multimap< int, int > MMII;
typedef multimap< string, int > MMSI;
//typedef unordered_map< int, int > uMII;
typedef pair< LL, LL > PLL;
typedef vector< LL > VL;
typedef vector< VL > VVL;
typedef priority_queue< int > PQIMax;
typedef priority_queue< int, VI, greater< int > > PQIMin;
const double EPS = 1e-8;
const LL inf = 0x7fffffff;
const LL infLL = 0x7fffffffffffffffLL;
const LL mod = 1e9 + 7;
const int maxN = 1e4 + 7;
const LL ONE = 1;
const LL evenBits = 0xaaaaaaaaaaaaaaaa;
const LL oddBits = 0x5555555555555555;

struct Article{
    vector< string > vs;
    
    string operator[] (int x) const {
        return vs[x];
    }
};
vector< Article > va;

istream& operator >> (istream& in, Article& x){
    string s;
    while(getline(cin, s)) {
        if(!s.size()) continue;
        if(s == "**********") break;
        x.vs.PB(s);
    }
    return in;
}

ostream& operator << (ostream& out, const Article& x){
    foreach(i, x.vs) out << *i << endl;
    return out;
}

string tmp; 
int N, M;
set< string > exc = {"the", "a", "to", "and", "or", "not"};
map< string, set< PII > > dict; // 存文章号和行号的索引 
map< string, SI > dicta; // 只存文章号的索引 

void build_index(int a_id, const Article &a) {
    string t;
    Rep(i, a.vs.size()) {
        t = a[i];
        foreach(j, t) if(!isalpha(*j)) *j = ' ';
        stringstream sin(t);
        
        while(sin >> t) {
            TOLOWER(t);
            if(exc.find(t) == exc.end()) {
                dict[t].insert(MP(a_id, i));
                dicta[t].insert(a_id);
            }
        }
    }
}

int main(){
    //freopen("MyOutput.txt","w",stdout);
    //freopen("input.txt","r",stdin);
    //INIT();
    scanf("%d
", &N);
    Rep(i, N) {
        Article t;
        cin >> t;
        build_index(va.size(), t);
        va.PB(t);
    }
    
    scanf("%d
", &M);
    Rep(i, M) {
        getline(cin, tmp);
        if(tmp.find("NOT") != string::npos) {
            tmp = tmp.substr(tmp.find(' ') + 1);
            int cnt = 0;
            
            Rep(i, N) {
                if(dicta[tmp].find(i) == dicta[tmp].end()) {
                    if(cnt++) printf("----------
");
                    cout << va[i];
                }
            }
            if(!cnt) printf("Sorry, I found nothing.
");
        } 
        else {
            set< PII > x;
            if(tmp.find("AND") != string::npos) {
                string a = tmp.substr(0, tmp.find(' '));
                string b = tmp.substr(tmp.find(' ') + 5);
                set< int > sx;
                
                set_intersection(ALL(dicta[a]), ALL(dicta[b]), INS(sx));
                
                foreach(i, dict[a]) if(sx.find(i->ft) != sx.end()) x.insert(*i);
                foreach(i, dict[b]) if(sx.find(i->ft) != sx.end()) x.insert(*i);
            }
            else if(tmp.find("OR") != string::npos) {
                string a = tmp.substr(0, tmp.find(' '));
                string b = tmp.substr(tmp.find(' ') + 4);
                
                set_union(ALL(dict[a]), ALL(dict[b]), INS(x));
            }
            else x = dict[tmp];
            
            int id = x.begin()->ft;
            foreach(i, x) {
                if(i->ft != id) {
                    printf("----------
");
                    id = i->ft;
                }
                cout << va[id][i->sd] << endl;
            } 
            if(x.empty()) printf("Sorry, I found nothing.
");
        }
        printf("==========
");
    }
    return 0;
}