fizzbuzz puzzle

This commit is contained in:
Neale Pickett 2011-10-10 22:28:56 -06:00
parent 7e8e61cb6c
commit 57796bb819
1 changed files with 85 additions and 0 deletions

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@ -0,0 +1,85 @@
#include <stdio.h>
#include <stdlib.h>
/*
* How this works:
*
* You have to provide this with the output of a fizzbuzz program to get
* it to decode the token.
*
* Provide the encoded token on fd 3, and it will output the decode
* provided correct input. If you provided the decoded token, it will
* encode it. In other words, encode(x) = decode(x).
*
*
* Here's a fizzbuzz program in bourne shell:
*
* for i in $(seq 100); do
* if [ $(expr $i % 15) = 0 ]; then
* echo 'FizzBuzz'
* elif [ $(expr $i % 3) = 0 ]; then
* echo 'Fizz'
* elif [ $(expr $i % 5) = 0 ]; then
* echo 'Buzz'
* else
* echo $i
* fi
* done
*
*/
char craptable[] = {
0x64, 0xd4, 0x11, 0x55, 0x50, 0x16, 0x61, 0x02,
0xf7, 0xfd, 0x63, 0x36, 0xd9, 0xa6, 0xf2, 0x29,
0xad, 0xfb, 0xed, 0x7a, 0x06, 0x91, 0xe7, 0x67,
0x80, 0xb6, 0x53, 0x2c, 0x43, 0xf9, 0x3c, 0xf2,
0x83, 0x5c, 0x25, 0xee, 0x21
};
int
main(int argc, char *argv[])
{
int i;
char token[100];
size_t tokenlen;
{
FILE *tokenin = fdopen(3, "r");
if (! tokenin) {
printf("Somebody didn't read the instructions.\n");
return 1;
}
tokenlen = fread(token, 1, sizeof(token), tokenin);
fclose(tokenin);
}
for (i=1; i <= 100; i += 1) {
char l[100];
fgets(l, sizeof(l), stdin);
if (0 == i % 15) {
if (0 != strcmp("FizzBuzz\n", l)) break;
} else if (0 == i % 3) {
if (0 != strcmp("Fizz\n", l)) break;
} else if (0 == i % 5) {
if (0 != strcmp("Buzz\n", l)) break;
} else {
if (atoi(l) != i) break;
}
token[i % tokenlen] ^= i;
token[i % tokenlen] ^= craptable[i % sizeof(craptable)];
}
if (101 == i) {
fwrite(token, tokenlen, 1, stdout);
} else {
printf("Next time, FizzBuzz me.\n");
}
return 0;
}