POJ 2050 Searching the Web
题意简述：做一个极其简单的搜索系统，对以下四种输入进行分析与搜索：
1. 只有一个单词：如 term， 只需找到含有这个单词的document，然后把这个document的含有这个单词term的那些行输出。
2.term1 AND term2， 找到同时含有term1 和 term2 的document，然后把这个document的含有这个单词term1 或 term2 的那些行输出。
3.term1 OR term2， 找到含有term1 或 term2 的document，然后把这个document的含有这个单词term1 或 term2 的那些行输出。
4.NOT term，将不含有 term的document全部输出
思路简述：
做一个set集合 Src， 记录了一个单词出现在哪些文件的哪些行；用一个map做映射，指出一个单词出现在哪些文件中，这样子，如果是两个单词，可以分别求出各个单词属于哪些文件，根据“AND”则进行set_intersection运算， 根据“OR”进行set_union运算。
/*
Poj 2050
Emerald
10 May 2015
*/
#include <iostream>
#include <cstring>
#include <cstdio>
#include <cctype>
#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <algorithm>
using namespace std;
class Figure{ // meaning : a word can be found in the lineOrder'th line of the docOrder'th Doc
public:
int docOrder, lineOrder;
Figure() {}
Figure( int d, int l ) {
docOrder = d;
lineOrder = l;
}
};
bool operator < ( const Figure f1, const Figure f2 ) { // the comparisions used in set
if( f1.docOrder!=f2.docOrder ) {
return f1.docOrder < f2.docOrder;
} else {
return f1.lineOrder < f2.lineOrder;
}
}
class Doc{ // meaning : the order of a Doc, and how many lines the Doc contains
public :
int docOrder, lineLimit;
Doc() {}
Doc( int d, int l ) {
this->docOrder = d;
this->lineLimit = l;
}
};
// set < Figure > src; // this defination defines an accurate instant
typedef set < Figure > Src; // a src contains the figures of a word
typedef set < int > docSrc;
map < string, docSrc > docMap; // referring to a word, wordLine get a line
map < string, Src > dict;
map < Figure, string > wordLine; // referring to a word, wordLine get a line
vector < Doc > docs;
const string DOC_END = "**********";
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())
void Standard( string &line ); // make words tolower and other chars to whitespace
void WordRecord( string &line, int docOrder, int lineOrder ); // transfer words into src
void PrintSrc( Src &src ); // print as the problem commands
void WordsToFigure( Src &src, docSrc &dsrc, string& w1, string& w2 ); // know the docs and words, get target figures
void NotWord( string& word, Src &src ); // not the word w
int main() {
int allDocs, queries;
// input docs
scanf( "%d", &allDocs );
cin.get();
for( int i=0; i<allDocs; i++ ) {
string line;
int lineCounter = 0;
while( getline( cin, line ) && line != DOC_END ) { // read until end
wordLine[ Figure( i, lineCounter ) ] = line;
Standard( line );
WordRecord( line, i, lineCounter ++ );
}
docs.push_back( Doc( i, lineCounter ) );
}
// input queries
string command;
scanf( "%d", &queries );
cin.get();
while( queries -- ) {
getline( cin, command );
Standard( command );
Src src;
if( command.find_last_of( ' ' ) == string::npos ) { // no whitespace
Standard( command );
src = dict[ command ];
} else if( command.find_last_of( ' ' ) != command.find_first_of( ' ' ) ) { // if there're two different whitespaces
stringstream ss( command ); // xxx AND/OR xxx
string w1, w2, connected;
ss >> w1 >> connected >> w2;
docSrc dSrc1 = docMap[ w1 ];
docSrc dSrc2 = docMap[ w2 ];
docSrc dsrc;
if( connected == "and" ) {
set_intersection( ALL( dSrc1 ), ALL( dSrc2 ), INS( dsrc ) ); // intersection
} else {
set_union( ALL( dSrc1 ), ALL( dSrc2 ), INS( dsrc ) ); // union
}
WordsToFigure( src, dsrc, w1, w2 );
} else { // only one whitespace -> Not xxx
stringstream ss( command );
string w1;
ss >> w1 >> w1;
NotWord( w1, src );
}
PrintSrc( src );
}
return 0;
}
void Standard( string &line ) {
int length = line.length();
for( int i=0; i<length; i++ ) {
if( isalpha( line[i] ) ) {
line[i] = tolower( line[i] ); // tolower, such as 'A' to 'a'
} else {
line[i] = ' '; // if c isn't a alpha, c will be transferred to a whitespace
}
}
}
void WordRecord( string &line, int docOrder, int lineOrder ) {
stringstream ss( line );
string word;
while( ss >> word ) {
if( dict.count( word ) ) { // whether the word has been found in the total input
if( !dict[word].count( Figure( docOrder, lineOrder ) ) ) { // whether the word has been found in this line
dict[word].insert( Figure( docOrder, lineOrder ) ) ;
}
} else {
Src src;
src.insert( Figure( docOrder, lineOrder ) );
dict[ word ] = src;
}
if( docMap.count( word ) ) { // whether the word has been found in this document
docMap[word].insert( docOrder );
} else {
docSrc ds;
docMap[word] = ds;
docMap[word].insert( docOrder );
}
}
}
void PrintSrc( Src &src ) { // print the result
if( src.size() == 0 ) {
printf("Sorry, I found nothing.\n");
printf( "==========\n" );
return ;
}
Src :: iterator it = src.begin(), bef; // bef represents the former one
printf( "%s\n", wordLine[ *it ].c_str() );
bef = it++;
while( it != src.end() ) {
if( it->docOrder != bef->docOrder ) {
printf( "----------\n" );
}
printf( "%s\n", wordLine[ *it ].c_str() );
bef = it;
it ++;
}
printf( "==========\n" );
}
void WordsToFigure( Src &src, docSrc &dsrc, string& w1, string& w2 ) {
docSrc :: iterator it;
for( it=dsrc.begin(); it != dsrc.end(); it ++ ) {
Src :: iterator it2 ;
for( it2 = dict[ w1 ].begin(); it2 !=dict[w1].end(); it2 ++ ) {
if( *it == it2 -> docOrder ) {
src.insert( *it2 ); // the w1 appears in this line of this document
}
}
for( it2 = dict[ w2 ].begin(); it2 !=dict[w2].end(); it2 ++ ) {
if( *it == it2 -> docOrder ) {
src.insert( *it2 ); // the w1 appears in this line of this document
}
}
}
}
void NotWord( string& word, Src &src ) { // not this word
docSrc dsrc = docMap[ word ];
vector< Doc > :: iterator it;
for( it = docs.begin(); it != docs.end(); it ++ ) {
if( !dsrc.count( it->docOrder ) ) {
for( int i=0; i< it->lineLimit; i ++ ) {
src.insert( Figure( it->docOrder, i ) );
}
}
}
}