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#include <stdio.h>
#include <stdlib.h>
#define UNIQ_CHARS 14
/*
* Tests if first UNIQ_CHARS chars of buf are all different.
* Returns 1 if there is at least one common char, 0 if none.
*/
int
test_common(char *buf) {
int common = 0;
for (int i = 0; i < UNIQ_CHARS - 1; i++) {
for (int j = i + 1; j < UNIQ_CHARS; j++) {
if (buf[i] == buf[j]) {
common = 1;
goto done;
}
}
}
done:
return common;
}
int
main(int argc, char **argv) {
char *buf = NULL;
size_t buflen = 0;
ssize_t n;
FILE *f;
if (argc != 2) {
fprintf(stderr, "usage: %s input\n", argv[0]);
return 1;
}
f = fopen(argv[1], "r");
if (f == NULL) {
perror(argv[1]);
return 1;
}
while ((n = getline(&buf, &buflen, f)) != -1) {
int i, solution = -1;
if (buf[n - 1] == '\n') {
buf[n - 1] = '\0';
n--;
}
for (i = 0; i < n - UNIQ_CHARS - 1; i++) {
if (test_common(&buf[i]) == 0) {
solution = i + UNIQ_CHARS;
break;
}
}
if (solution != -1) {
printf("%d\n", solution);
break;
}
}
free(buf);
fclose(f);
return 0;
}
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