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#include <ctype.h>
#include <regex.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct crate {
struct crate * next;
char id;
};
int
crates_move(struct crate ** stack, int stacks, int dest, int src, int count)
{
int i;
if (dest < 0 || dest >= stacks
|| src < 0 || src >= stacks)
{
fprintf(stderr, "Invalid src/dest stack (%d/%d/%d)\n",
stacks, dest, src);
return -1;
}
for (i = 0; i < count; ++i) {
struct crate * c;
if (stack[src] == NULL) {
fprintf(stderr, "No crates available in stack %d\n",
src);
return -1;
}
c = stack[src];
stack[src] = c->next;
c->next = stack[dest];
stack[dest] = c;
}
return 0;
}
int
crates_dump(struct crate ** stack, int stacks)
{
int i;
for (i = 0; i < stacks; ++i) {
struct crate * c;
fprintf(stderr, "%d:", i + 1);
for (c = stack[i]; c != NULL; c = c->next) {
fprintf(stderr, " %c", c->id);
}
fprintf(stderr, "\n");
}
fprintf(stderr, "\n");
return 0;
}
int
main()
{
char buf[BUFSIZ];
int stacks = 0, i;
struct crate ** stack = NULL;
regex_t movecmd;
while (fgets(buf, sizeof(buf), stdin)) {
int len;
len = strlen(buf);
if (len == 1 && buf[0] == '\n') {
break;
}
if (stacks == 0 && stack == NULL) {
if (len % 4 != 0) {
fprintf(stderr, "Unexpected first line width: %d\n", len);
return -1;
}
stacks = len / 4;
stack = calloc(stacks, sizeof(struct crate *));
}
if (len != stacks * 4) {
fprintf(stderr, "Unexpected input line width: %d/%d\n", len, stacks * 4);
return -1;
}
for (i = 0; i < stacks; ++i) {
if (isupper(buf[i * 4 + 1])) {
struct crate ** pc = stack + i;
while (*pc != NULL)
pc = &(*pc)->next;
*pc = malloc(sizeof(struct crate));
(*pc)->next = NULL;
(*pc)->id = buf[i * 4 + 1];
}
}
#ifdef CRATES_DUMP
crates_dump(stack, stacks);
#endif
}
regcomp(&movecmd, "move ([[:digit:]]+) from ([[:digit:]]+) to ([[:digit:]]+)\n", REG_EXTENDED);
while (fgets(buf, sizeof(buf), stdin)) {
regmatch_t matches[4];
if (regexec(&movecmd, buf, 4, matches, 0) != 0) {
fprintf(stderr, "Unexpected move command: %s\n", buf);
}
crates_move(stack, stacks,
atoi(buf + matches[3].rm_so) - 1,
atoi(buf + matches[2].rm_so) - 1,
atoi(buf + matches[1].rm_so));
#ifdef CRATES_DUMP
crates_dump(stack, stacks);
#endif
}
regfree(&movecmd);
for (i = 0; i < stacks; ++i) {
fputc(stack[i] ? stack[i]->id : ' ', stdout);
}
fputc('\n', stdout);
return 0;
}
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