UVa:1597 - Searching the Web

<span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">题目思路：</span>

<span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">首先需要构造出关键词的字典，提取关键字有一个小技巧：可以把字符串中所有非英文字母化为空格，然后用stringstream读取</span>

void updatedic(string str,int doc_id,int row_id)
{
	string word;
	for(int i=0;i<str.size();i++)
	{
		if(isalpha(str[i]))
			str[i]=tolower(str[i]);
		else
			str[i]=' ';
	}
	stringstream s(str);
	while(s>>word)
		dic[word].insert(pair<int,int>(doc_id,row_id));
}

#include <iostream>
#include <fstream>
#include <string>
#include <map>
#include <vector>
#include <sstream>
#include <set>
#include <algorithm>
#include <iterator>

using namespace std;

map<string ,set<pair<int,int>>> dic;
vector<vector<string>> doc;

#define FILE

void updatedic(string str,int doc_id,int row_id)
{
	string word;
	for(int i=0;i<str.size();i++)
	{
		if(isalpha(str[i]))
			str[i]=tolower(str[i]);
		else
			str[i]=' ';
	}
	stringstream s(str);
	while(s>>word)
		dic[word].insert(pair<int,int>(doc_id,row_id));
}

void get_doc_id(set<pair<int,int>>table,set<int> &res)
{
	for(set<pair<int,int>>::iterator it=table.begin();it!=table.end();it++)
	{
		res.insert((*it).first);
	}
}

int main(int argc, char* argv[])
{
#ifdef FILE
	ifstream in("data.txt");
	ofstream out("output.txt");
	cin.rdbuf(in.rdbuf());
	cout.rdbuf(out.rdbuf());
#endif
	int N,M;
	string str;
	while(cin>>N)
	{
		cin.get();
		int doc_id=0;
		for(int i=0;i<N;i++)
		{
			int row_id=0;
			while(getline(cin,str))
			{
				if(str=="**********")
					break;
				else
				{
					if(doc_id==doc.size())
					{
						vector<string> temp;
						doc.push_back(temp);
					}
					doc[doc_id].push_back(str);
					updatedic(str,doc_id,row_id);
					row_id++;
				}
			}
			doc_id++;
		}
		cin>>M;
		cin.get();
		for(int i=0;i<M;i++)
		{
			getline(cin,str);
			if(str[0]=='N')
			{
				string keyword = str.substr(4);
				set<pair<int,int>>table = dic[keyword];
				if(table.size()==doc.size())
				{
					cout<<"Sorry, I found nothing."<<endl<<"=========="<<endl;
					continue;
				}
				map<int,int>res;
				for(set<pair<int,int>>::iterator it=table.begin();it!=table.end();it++)
				{
					pair<int,int> val= *it;
					res[val.first] = 1;
				}
				int num =0,doc_num=0 ;
				for(int i=0;i<doc.size();i++)
				{

					if(res.count(i)==0)
					{
						if(num!=0)
						{
							if(doc_num!=i)
							{
								cout<<"----------"<<endl;
								doc_num=i;
							}
						}
						num++;
						for(int j=0;j<doc[i].size();j++)
						{
							cout<<doc[i][j]<<endl;

						}
					}
				}
				cout<<"=========="<<endl;
			}
			else if(str.find("AND")!=string::npos)
			{
				int p = str.find("AND");
				string keyword1 = str.substr(0,p-1),keyword2 = str.substr(p+4);
				set<pair<int,int>>table1 = dic[keyword1];
				set<pair<int,int>>table2 = dic[keyword2];
				set<pair<int,int>>res;
				set<int> table,table1_temp,table2_temp;
				get_doc_id(table1,table1_temp);
				get_doc_id(table2,table2_temp);
				set_intersection(table1_temp.begin(),table1_temp.end(),table2_temp.begin(),table2_temp.end(),inserter(table,table.begin()));
				set_union(table1.begin(),table1.end(),table2.begin(),table2.end(),inserter(res,res.begin())); 
				if(table.size()==0)
				{
					cout<<"Sorry, I found nothing."<<endl<<"=========="<<endl;
					continue;
				}
				int doc_num=*(table.begin()),i=0;
				for(set<int>::iterator it=table.begin();it!=table.end();it++)
				{
					if(i!=0)
					{
						if((*it)!=doc_num)
						{
							cout<<"----------"<<endl;
							doc_num = *it;
						}
					}
					for(int j=0;j<doc[*it].size();j++)
					{

						if(res.find(pair<int,int>(*it,j))!=res.end())
						{
							cout<<doc[*it][j]<<endl;
							i++;
						}
					}
				}
				cout<<"=========="<<endl;
			}
			else if(str.find("OR")!=string::npos)
			{
				int p = str.find("OR");
				string keyword1 = str.substr(0,p-1),keyword2 = str.substr(p+3);
				set<pair<int,int>>table1 = dic[keyword1];
				set<pair<int,int>>table2 = dic[keyword2];
				set<pair<int,int>>res ;
				set_union(table1.begin(),table1.end(),table2.begin(),table2.end(),inserter(res,res.begin()));
				if(res.size()==0)
				{
					cout<<"Sorry, I found nothing."<<endl<<"=========="<<endl;
					continue;
				}
				int i =0;
				int doc_num=(*res.begin()).first;
				for(set<pair<int,int>>::iterator it=res.begin();it!=res.end();it++,i++)
				{
					pair<int,int> val= *it;
					if(i!=0)
					{
						if(val.first!=doc_num)
						{
							cout<<"----------"<<endl;
							doc_num = val.first;
						}

					}
					cout<<doc[val.first][val.second]<<endl;
					
				}
				cout<<"=========="<<endl;
			}
			else
			{
				string keyword = str;
				set<pair<int,int>>table = dic[keyword];
				if(table.size()==0)
				{
					cout<<"Sorry, I found nothing."<<endl<<"=========="<<endl;
					continue;
				}
				int i =0,doc_num=(*table.begin()).first;
				for(set<pair<int,int>>::iterator it=table.begin();it!=table.end();it++,i++)
				{
					pair<int,int> val= *it;
					if(i!=0)
					{
						if(doc_num!=val.first)
						{
							cout<<"----------"<<endl;
							doc_num=val.first;
						}
					}
					cout<<doc[val.first][val.second]<<endl;
				}
				cout<<"=========="<<endl;
			}
		}
		dic.clear();
		doc.clear();
	}
	return 0;
}