ptt.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/time.h>
#include <math.h>

char p[12][24] = {
	"abcdefghiklnopqrstuwxyzm", // ab
	"abcdefghiklopqrstuwxyzmn", // cd
	"abcdefghiklpqrstuwxyzmno", // ef
	"abcdefghiklqrstuwxyzmnop", // gh 
	"abcdefghiklrstuwxyzmnopq", // ik
	"abcdefghiklstuwxyzmnopqr", // lm
	"abcdefghikltuwxyzmnopqrs", // no
	"abcdefghikluwxyzmnopqrst", // pq
	"abcdefghiklwxyzmnopqrstu", // rs
	"abcdefghiklxyzmnopqrstuw", // tu
	"abcdefghiklyzmnopqrstuwx", // wx
	"abcdefghiklmnopqrstuwxyz"  // yz
};

/* void *portaDecipher (char *key, char *out)
{
	int i;
	int period = strlen(key);
	int len = strlen(ct);

	for (i = 0; i < len; i++)
	{
		int j = (strchr(c, key[i % period])-c) / 2; // 0 to 11
		int k = (strchr(p[j], ct[i])-p[j]); // 0 to 23
		// now 0 to 11 goes to 12 to 23; 12 to 23 goes to 0 to 11
		if (k < 12) k+= 12; else k-=12;
		out[i] = p[j][k];
	}
	out[len] = 0;
} */

main(int argc, char **argv)
{

	char ct[20];
	if (argc != 2) exit (1);

	strcpy(ct,argv[1]);

	while (1)
	{
		char pt[20];
		int i,len,poss=0;

		fscanf(stdin,"%s",pt);
		if (feof(stdin)) break;

		len = strlen(pt);

		for (i = 0; i < len; i++)
		{
			int s1,s2,a,good=0;
			for (a = 0; a < 12; a++)
			{
				s1 = (strchr(p[a], pt[i]) - p[a]);
				s2 = (strchr(p[a], ct[i]) - p[a]);
				//if (s1/12 != s2/12 && s1%12 == s2%12) {printf("%d %d\n",i,a); good = 1; }
				if (s1/12 != s2/12 && s1%12 == s2%12) good = 1; 
			}
			if (good == 1) poss++;
		}
		if (poss == len) printf("%s\n",pt);
	}
}