imported>Unknown at 05:23, 7 February 2021

2021-02-07T05:23:03Z

New page

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

==== 코드 ====
// 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];
}
}
}
----
[[CryptKicker2]] [[문보창]]

CryptKicker2/문보창 - Revision history

imported>Unknown at 05:23, 7 February 2021