advent-of-code-2021/3/3-2.c

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2021-12-03 20:32:57 +08:00
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include "../check_alloc.h"
#define INPUT_PATH "input"
#define WIDTH 12
// LIST DATASTRUCTURE
#define INITIAL_SIZE 20
typedef struct
{
char **list;
size_t size;
size_t capacity;
} LIST;
void free_list(LIST *list)
{
free(list->list);
free(list);
}
void delete_list(LIST *list)
{
for (size_t i = 0; i < list->size; i++)
{
free(list->list[i]);
}
free_list(list);
}
LIST *new_list(void)
{
LIST *p_list = calloc(1, sizeof(LIST));
p_list->capacity = INITIAL_SIZE;
p_list->list = calloc(p_list->capacity, sizeof(char *));
return p_list;
}
void add_list(LIST *list, char *elem)
{
if (list->size >= list->capacity)
{
list->capacity *= 2;
list->list = realloc(list->list, list->capacity * sizeof(char *));
CHECK_ALLOC(list->list);
}
list->list[list->size] = elem;
list->size++;
}
//
LIST *read_file(char *path)
{
FILE *p_file = fopen(path, "r");
LIST *p_list = new_list();
char line[WIDTH + 2];
while (fgets(line, sizeof line, p_file) != NULL)
{
add_list(p_list, strdup(line));
}
return p_list;
}
char common_value(LIST *list, char index)
{
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unsigned int one = 0;
unsigned int zero = 0;
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for (size_t i = 0; i < list->size; i++)
{
if (list->list[i][index] - '0')
{
one++;
}
else
{
zero++;
}
}
return one >= zero;
}
void partition(LIST *list, char index, bool co2, bool o2)
{
if (index >= WIDTH || list->size == 1)
{
if (co2)
printf("CO2\n");
else
printf("O2\n");
printf("%lu\n", strtol(list->list[0], NULL, 2));
return;
}
char common = common_value(list, index);
LIST *p_list_co2 = new_list();
LIST *p_list_o2 = new_list();
for (size_t i = 0; i < list->size; i++)
{
if ((list->list[i][index] - '0') == common)
{
if (o2)
add_list(p_list_o2, list->list[i]);
}
else
{
if (co2)
add_list(p_list_co2, list->list[i]);
}
}
if (o2)
partition(p_list_o2, index + 1, false, true);
if (co2)
partition(p_list_co2, index + 1, true, false);
free_list(p_list_o2);
free_list(p_list_co2);
}
int main(int argc, char const *argv[])
{
LIST *list = read_file(INPUT_PATH);
partition(list, 0, true, true);
delete_list(list);
return 0;
}