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Crypt Kicker2/문보창

소감

2005/02/19 Accepted 0:00.006 64
암호화 방법이라. 재밌는 문제. 꼼꼼히 따져주기만 하면 되는 문제.

코드

~cpp 
// no850 - Crypt Kicker2
#include <iostream>
#include <cstring>
#include <string>
#include <cctype>
using namespace std;

/* 평문공격법
"the quick brown fox jumps over the lazy dog"
43자
빈도수 4, 3, 2, 2, 2, 2, 1, ...
*/

const int MAX_LEN = 81;
const int PROPER_LEN = 43;

bool input(string & s, char * rul);
bool isreplace(char * str);
void findRule(char * str, char * rul);
void decoding(string & s, char * rul);
inline void output(string & s) { cout << s; }

int main()
{
	int nCase;
	cin >> nCase;
	cin.get(), cin.get();


	char rule[26];
	int i;
	for (i=0; i<nCase; i++)
	{
		string s;
		if (input(s, rule))
		{
			decoding(s, rule);
			output(s);
		}
		else
			cout << "No solution.\n";
		if (i != nCase-1)
			cout << endl;
	}
	return 0;
}

bool input(string & s, char * rul)
{
	char str[MAX_LEN];
	bool serch = false;
	while (cin.peek() != '\n' && cin.peek() != EOF)
	{
		cin.getline(str, MAX_LEN, '\n');
		if (isreplace(str)) 
		{
			serch = true;
			findRule(str, rul);
		}
		s += str;
		s += '\n';
	}
	cin.get();
	if (serch)
		return true;
	return false;
}

bool isreplace(char * str)
{
	int len = strlen(str);
	if (len != PROPER_LEN)			// 1차 - 길이 비교
		return false;
	// 여백 위치 비교
	else if (!(str[3] == ' ' && str[9] == ' ' && str[15] == ' ' && str[19] == ' ' && str[25] == ' ' && 
		str[30] == ' ' && str[34] == ' ' && str[39] == ' '))
		return false;
	int i;
	int count2, count3, count4;
	count2 = count3 = count4 = 0;
	int alpa[26] = {0,};
	for (i=0; i<len; i++)
	{
		if (isalpha(str[i]))
			alpa[str[i]-97]++;	
	}
	for (i=0; i<26; i++)
	{
		if (alpa[i] == 2)
			count2++;
		else if (alpa[i] == 3)
			count3++;
		else if (alpa[i] == 4)
			count4++;
	}
	if (!(count2 == 4 && count3 == 1 && count4 == 1))		// 알파벳 빈도수 조사
		return false;
	return true;
}

void findRule(char * str, char * rul)
{
	char strOrin[] = "the quick brown fox jumps over the lazy dog";
	int i;
	for (i=0; i<PROPER_LEN; i++)
	{
		if (isalpha(str[i]))
		{
			rul[str[i]-97] =  strOrin[i];
		}
	}
}

void decoding(string & s, char * rul)
{
	int i;
	int len = s.size();
	for (i=0; i<len; i++)
	{
		if (isalpha(s[i]))
		{
			s[i] = rul[s[i]-97];		
		}
	}
}
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