Advent of Code 2018
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75 lines
1.7 KiB

#include <stdlib.h>
#include <stdio.h>
#include <glib.h>
/*
* Apparently using a hash table for this is much faster...
*
* $ time ./main
* 69285
* ./main 271,27s user 0,11s system 99% cpu 4:33,04 total
* $ time ./main_hash
* 69285
* ./main_hash 0,13s user 0,02s system 98% cpu 0,156 total
*/
#ifndef USE_HASH
gpointer g_array_lookup(GArray *array, gpointer item, guint size)
{
for (gchar *i = array->data; i < array->data + array->len * size; i += size) {
if (memcmp(i, item, size) == 0) {
return i;
}
}
return NULL;
}
#endif
int main()
{
long value = 0;
char *line = NULL;
size_t line_len = 0;
FILE *f = fopen("input", "r");
if (!f) {
perror("input");
return 1;
}
#ifdef USE_HASH
GHashTable *hash = g_hash_table_new(g_direct_hash, g_direct_equal);
g_hash_table_insert(hash, GINT_TO_POINTER(value), GINT_TO_POINTER(TRUE));
#else
GArray *array = g_array_new(FALSE, FALSE, sizeof(long));
g_array_append_val(array, value);
#endif
while (1) {
rewind(f);
while (getline(&line, &line_len, f) != -1) {
long number = strtol(line, NULL, 0);
value += number;
#ifdef USE_HASH
if (g_hash_table_lookup(hash, GINT_TO_POINTER(value))) goto found;
g_hash_table_insert(hash, GINT_TO_POINTER(value), GINT_TO_POINTER(TRUE));
#else
if (g_array_lookup(array, &value, sizeof(long))) goto found;
g_array_append_val(array, value);
#endif
}
}
found:
printf("%ld\n", value);
#ifdef USE_HASH
g_hash_table_destroy(hash);
#else
g_array_free(array, TRUE);
#endif
free(line);
fclose(f);
return 0;
}