Programming_Course/Chapter 8/8-5gen_sentence/8-5grammar.cpp

#ifdef _MSC_VER
#pragma warning(disable:4503)      // `silence compiler complaints about generated names being too long'
#endif

#include <algorithm>
#include <cstdlib>
#include <iostream>
#include <map>
#include <stdexcept>
#include <string>
#include <vector>

#include "split.h"
#include <time.h>

using std::istream;           using std::cin;
using std::copy;              using std::cout;
using std::endl;              using std::find;
using std::getline;           using std::logic_error;
using std::map;               using std::string;
using std::vector;            using std::domain_error;
using std::rand;

typedef vector<string> Rule;
typedef vector<Rule> Rule_collection;
typedef map<string, Rule_collection> Grammar;

// read a grammar from a given input stream
Grammar read_grammar(istream& in)
{
	Grammar ret;
	string line;

	// read the input
	while (getline(in, line)) {

		// `split' the input into words
		vector<string> entry = split(line);

		if (!entry.empty())
			// use the category to store the associated rule
			ret[entry[0]].push_back(
				Rule(entry.begin() + 1, entry.end()));
	}
	return ret;
}

void gen_aux(const Grammar&, const string&, vector<string>&);

int nrand(int);

vector<string> gen_sentence(const Grammar& g)
{
	vector<string> ret;
	gen_aux(g, "<sentence>", ret);
	return ret;
}

bool bracketed(const string& s)
{
	return s.size() > 1 && s[0] == '<' && s[s.size() - 1] == '>';
}

void
gen_aux(const Grammar& g, const string& word, vector<string>& ret)
{

	if (!bracketed(word)) {
		ret.push_back(word);
	} else {
		// locate the rule that corresponds to `word'
		Grammar::const_iterator it = g.find(word);
		if (it == g.end())
			throw logic_error("empty rule");

		// fetch the set of possible rules
		const Rule_collection& c = it->second;

		// from which we select one at random
		const Rule& r = c[nrand(c.size())];

		// recursively expand the selected rule
		for (Rule::const_iterator i = r.begin(); i != r.end(); ++i)
			gen_aux(g, *i, ret);
	}
}

int main()
{
	// generate the sentence
	vector<string> sentence = gen_sentence(read_grammar(cin));

	// write the first word, if any
#ifdef _MSC_VER
	std::vector<string>::const_iterator it = sentence.begin();
#else
	vector<string>::const_iterator it = sentence.begin();
#endif
	if (!sentence.empty()) {
		cout << *it;
		++it;
	}

	// write the rest of the words, each preceded by a space
	while (it != sentence.end()) {
		cout << " " << *it;
		++it;
	}

	cout << endl;
	return 0;
}

// return a random integer in the range `[0,' `n)'
int nrand(int n)
{
	if (n <= 0 || n > RAND_MAX)
		throw domain_error("Argument to nrand is out of range");

	const int bucket_size = RAND_MAX / n;
	int r;

	do r = rand() / bucket_size;
	while (r >= n);

	return r;
}



#ifdef _MSC_VER
#pragma warning(disable:4503)      // <20>رձ<D8B1><D5B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>棬<EFBFBD><E6A3AC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ɵ<EFBFBD><C9B5><EFBFBD><EFBFBD>ƹ<EFBFBD><C6B9><EFBFBD><EFBFBD>ı<EFBFBD>Թ
#endif

#include <algorithm>      // <20><><EFBFBD><EFBFBD><EFBFBD>㷨<EFBFBD>⣬<EFBFBD>ṩ<EFBFBD><E1B9A9><EFBFBD>õ<EFBFBD><C3B5>㷨
#include <cstdlib>        // <20><><EFBFBD><EFBFBD>C<EFBFBD><43>׼<EFBFBD>⣬<EFBFBD><E2A3AC><EFBFBD><EFBFBD>rand()<29><><EFBFBD><EFBFBD>
#include <iostream>       // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>׼<EFBFBD><D7BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
#include <map>            // <20><><EFBFBD><EFBFBD>ӳ<EFBFBD><D3B3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>map<61><70><EFBFBD><EFBFBD>
#include <stdexcept>      // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>׼<EFBFBD>쳣<EFBFBD>⣬<EFBFBD>ṩ<EFBFBD>߼<EFBFBD><DFBC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>쳣
#include <string>         // <20><><EFBFBD><EFBFBD><EFBFBD>ַ<EFBFBD><D6B7><EFBFBD><EFBFBD><EFBFBD>
#include <vector>         // <20><><EFBFBD>붯̬<EBB6AF><CCAC><EFBFBD>飨vector<6F><72><EFBFBD><EFBFBD>
#include "split.h"        // <20><><EFBFBD><EFBFBD><EFBFBD>Զ<EFBFBD><D4B6><EFBFBD><EFBFBD><EFBFBD>split.hͷ<68>ļ<EFBFBD><C4BC><EFBFBD><EFBFBD>ٶ<EFBFBD><D9B6>ṩ<EFBFBD><E1B9A9><EFBFBD>ַ<EFBFBD><D6B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֹ<EFBFBD><D6B9>ܣ<EFBFBD>
#include <time.h>         // <20><><EFBFBD><EFBFBD>ʱ<EFBFBD><CAB1><EFBFBD>⣬֧<E2A3AC><D6A7><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>

using std::istream;           using std::cin;
using std::copy;              using std::cout;
using std::endl;              using std::find;
using std::getline;           using std::logic_error;
using std::map;               using std::string;
using std::vector;            using std::domain_error;
using std::rand;              // <20><><EFBFBD><EFBFBD>rand<6E><64><EFBFBD><EFBFBD>

// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ַ<EFBFBD><D6B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ϣ<EFBFBD><CFA3><EFBFBD><EFBFBD>﷨<EFBFBD><EFB7A8><EFBFBD><EFBFBD><EFBFBD>򼯺ϣ<F2BCAFBA><CFA3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
typedef vector<string> Rule;  // һ<><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ַ<EFBFBD><D6B7><EFBFBD><EFBFBD>ļ<EFBFBD><C4BC><EFBFBD>
typedef vector<Rule> Rule_collection;  // <20><><EFBFBD>򼯺<EFBFBD><F2BCAFBA>ǹ<EFBFBD><C7B9><EFBFBD><EFBFBD>ļ<EFBFBD><C4BC><EFBFBD>
typedef map<string, Rule_collection> Grammar;  // <20>﷨<EFBFBD><EFB7A8>һ<EFBFBD><D2BB>ӳ<EFBFBD>䣺<EFBFBD><E4A3BA><EFBFBD><EFBFBD> -> <20><><EFBFBD>򼯺<EFBFBD>

// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ж<EFBFBD>ȡ<EFBFBD>﷨<EFBFBD><EFB7A8><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Grammar read_grammar(istream& in) {
	Grammar ret;  // <20><><EFBFBD>ڴ洢<DAB4>﷨
	string line;

	// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡÿһ<C3BF><D2BB>
	while (getline(in, line)) {
		// <20><><EFBFBD><EFBFBD>ǰ<EFBFBD>в<EFBFBD><D0B2>ֳɵ<D6B3><C9B5><EFBFBD>
		vector<string> entry = split(line);

		// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֳ<EFBFBD><D6B3>ĵ<EFBFBD><C4B5>ʲ<EFBFBD>Ϊ<EFBFBD>գ<EFBFBD><D5A3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>洢<EFBFBD><E6B4A2><EFBFBD><EFBFBD>
		if (!entry.empty())
			ret[entry[0]].push_back(
				Rule(entry.begin() + 1, entry.end()));  // ʹ<><CAB9><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊkey<65><79><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊvalue
	}
	return ret;  // <20><><EFBFBD><EFBFBD><EFBFBD>﷨
}

// <20>ݹ<EFBFBD><DDB9><EFBFBD><EFBFBD>ɾ<EFBFBD><C9BE>ӵĸ<D3B5><C4B8><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
void gen_aux(const Grammar&, const string&, vector<string>&);

// <20><><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD>Χ<EFBFBD><CEA7>[0, n)<29>ڵ<EFBFBD><DAB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
int nrand(int);

// <20><><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD>ӣ<EFBFBD><D3A3><EFBFBD><EFBFBD><EFBFBD>gen_aux<75><78><EFBFBD>еݹ<D0B5><DDB9><EFBFBD><EFBFBD><EFBFBD>
vector<string> gen_sentence(const Grammar& g) {
	vector<string> ret;
	gen_aux(g, "<sentence>", ret);  // <20><><sentence><3E><>ʼ<EFBFBD><CABC><EFBFBD>ɾ<EFBFBD><C9BE><EFBFBD>
	return ret;
}

// <20>ж<EFBFBD>һ<EFBFBD><D2BB><EFBFBD>ַ<EFBFBD><D6B7><EFBFBD><EFBFBD>Ƿ<EFBFBD><C7B7>DZ<EFBFBD><C7B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ű<EFBFBD>Χ<EFBFBD><CEA7>
bool bracketed(const string& s) {
	return s.size() > 1 && s[0] == '<' && s[s.size() - 1] == '>';
}

// <20>ݹ<EFBFBD><DDB9><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ɾ<EFBFBD><C9BE><EFBFBD><EFBFBD>е<EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD>
void gen_aux(const Grammar& g, const string& word, vector<string>& ret) {
	if (!bracketed(word)) {
		ret.push_back(word);  // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>DZ<EFBFBD><C7B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ű<EFBFBD>Χ<EFBFBD>ĵ<EFBFBD><C4B5>ʣ<EFBFBD>ֱ<EFBFBD>Ӽ<EFBFBD><D3BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
	}
	else {
		// <20><><EFBFBD>Ҷ<EFBFBD>Ӧ<EFBFBD>Ĺ<EFBFBD><C4B9><EFBFBD>
		Grammar::const_iterator it = g.find(word);
		if (it == g.end())  // <20><><EFBFBD><EFBFBD>û<EFBFBD><C3BB><EFBFBD>ҵ<EFBFBD><D2B5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>׳<EFBFBD><D7B3>쳣
			throw logic_error("empty rule");

		// <20><>ȡ<EFBFBD>õ<EFBFBD><C3B5>ʵĹ<CAB5><C4B9>򼯺<EFBFBD>
		const Rule_collection& c = it->second;

		// <20>ӹ<EFBFBD><D3B9>򼯺<EFBFBD><F2BCAFBA><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ѡ<EFBFBD><D1A1>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
		const Rule& r = c[nrand(c.size())];

		// <20><>ѡ<EFBFBD>еĹ<D0B5><C4B9><EFBFBD><EFBFBD>е<EFBFBD>ÿ<EFBFBD><C3BF><EFBFBD><EFBFBD><EFBFBD>ʽ<EFBFBD><CABD>еݹ鴦<DDB9><E9B4A6>
		for (Rule::const_iterator i = r.begin(); i != r.end(); ++i)
			gen_aux(g, *i, ret);
	}
}

int main() {
	// <20><><EFBFBD>ɾ<EFBFBD><C9BE><EFBFBD>
	vector<string> sentence = gen_sentence(read_grammar(cin));

	// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD>ʣ<EFBFBD><CAA3><EFBFBD><EFBFBD><EFBFBD><EFBFBD>У<EFBFBD>
	vector<string>::const_iterator it = sentence.begin();
	if (!sentence.empty()) {
		cout << *it;
		++it;
	}

	// <20><><EFBFBD><EFBFBD>ʣ<EFBFBD><CAA3><EFBFBD>ĵ<EFBFBD><C4B5>ʣ<EFBFBD>ÿ<EFBFBD><C3BF><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ǰ<EFBFBD><C7B0>һ<EFBFBD><D2BB><EFBFBD>ո<EFBFBD>
	while (it != sentence.end()) {
		cout << " " << *it;
		++it;
	}

	cout << endl;  // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
	return 0;
}

// <20><><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Χ<EFBFBD><CEA7>[0, n)
int nrand(int n) {
	if (n <= 0 || n > RAND_MAX)
		throw domain_error("Argument to nrand is out of range");

	const int bucket_size = RAND_MAX / n;  // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȷֲ<C8B7>
	int r;

	// ȷ<><C8B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ч<EFBFBD><D0A7>Χ<EFBFBD><CEA7>
	do r = rand() / bucket_size;
	while (r >= n);

	return r;
}