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#include "allocator.h"
#include "aoc.h"
#include "dvec_s.h"
#include "util.h"
#include <assert.h>
#include <stdlib.h>
static void
deck_cut(struct dvec *deck, struct dvec *table, ssize_t in)
{
int *src, *dst;
size_t i, split, n;
n = deck->len;
split = in < 0 ? (size_t) ((ssize_t) deck->len + in) : (size_t) in;
src = deck->data;
dst = table->data;
for (i = 0; i < split; i++)
dst[i + n - split] = src[i];
for (i = split; i < n; i++)
dst[i - split] = src[i];
dvec_swap(deck, table);
}
static void
deal_increment(struct dvec *deck, struct dvec *table, size_t inc)
{
int *src, *dst;
size_t i, n, p;
n = deck->len;
src = deck->data;
dst = table->data;
p = 0;
for (i = 0; i < n; i++) {
dst[p] = src[i];
p = (p + inc) % n;
}
dvec_swap(deck, table);
}
static void
deal_new_stack(struct dvec *deck, struct dvec *table)
{
int *src, *dst;
size_t i, n;
n = deck->len - 1;
src = deck->data;
dst = table->data;
for (i = 0; i <= n; i++)
dst[n - i] = src[i];
dvec_swap(deck, table);
}
static size_t
find_card(struct dvec *deck, int card)
{
int *data;
size_t i, n;
n = deck->len;
data = deck->data;
for (i = 0; i < n; i++) {
if (data[i] == card)
return i;
}
return 0;
}
void
part1(void)
{
char line[256];
const char *lpos, *lend;
struct dvec deck, table;
size_t i, count;
size_t answer;
ssize_t val;
int target;
int *data;
if (!strcmp(aoc.inputfile, "input")) {
count = 10007;
target = 2019;
} else {
count = 10;
target = 9;
}
dvec_init(&deck, sizeof(int), count, &stdlib_strict_heap_allocator);
dvec_init(&table, sizeof(int), count, &stdlib_strict_heap_allocator);
dvec_add_slots(&deck, count);
dvec_add_slots(&table, count);
data = deck.data;
for (i = 0; i < count; i++)
data[i] = (int) i;
lpos = aoc.input;
lend = lpos + aoc.input_size;
while (readtok(line, sizeof(line), '\n', &lpos, lend)) {
if (sscanf(line, "deal with increment %li", &val) == 1) {
deal_increment(&deck, &table, (size_t) val);
} else if (sscanf(line, "cut %li", &val) == 1) {
deck_cut(&deck, &table, val);
} else if (!strcmp(line, "deal into new stack")) {
deal_new_stack(&deck, &table);
} else if (strspn(line, " \n\r\t\v") == strlen(line)) {
continue;
} else {
assert(false);
}
aoc_debug("%i pos: %lu\n", target, find_card(&deck, target));
}
answer = find_card(&deck, target);
aoc.answer = aprintf("%lu", answer);
aoc.solution = "7171";
dvec_deinit(&table);
dvec_deinit(&deck);
}
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