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#include "aoc.h"
#include "util.h"
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
int
check_pass_1(int *state)
{
int i;
for (i = 0; i < 5; i++)
if (state[i] == state[i+1])
break;
if (i != 5) aoc_debug("%i %i %i %i %i %i\n", state[0], state[1],
state[2], state[3], state[4], state[5]);
return i != 5;
}
int
check_pass_2(int *state)
{
int i;
for (i = 0; i < 5; i++) {
if (state[i] == state[i+1] && (i == 0 || state[i] != state[i-1])
&& (i == 4 || state[i] != state[i+2]))
break;
}
if (i != 5) aoc_debug("%i %i %i %i %i %i\n", state[0], state[1],
state[2], state[3], state[4], state[5]);
return i != 5;
}
void
count_valid(int *state, int *end, int pinit, int pend,
int index, int *count, int (*check_pass)(int*))
{
int i;
if (index == 6) {
*count += check_pass(state);
return;
}
if (index && pinit && state[index-1] > state[index]) {
pinit = 0;
state[index] = state[index-1];
} else if (index && !pinit) {
state[index] = state[index-1];
}
for (i = state[index]; i <= (pend ? end[index] : 9); i++) {
state[index] = i;
count_valid(state, end, pinit, pend && (i == end[index]),
index+1, count, check_pass);
}
state[index] = 0;
}
void
read_state(char *str, int *state)
{
int i;
for (i = 0; i < 6; i++)
state[i] = str[i] - '0';
}
void
part1(void)
{
int start[6], end[6];
char *tok;
int count;
tok = strchr(aoc.input, '-');
if (!tok) die("main: bad input");
read_state(aoc.input, start);
read_state(tok+1, end);
count = 0;
count_valid(start, end, 1, 1, 0, &count, check_pass_1);
aoc.answer = aprintf("%i", count);
aoc.solution = "966";
}
void
part2(void)
{
int start[6], end[6];
char *tok;
int count;
tok = strchr(aoc.input, '-');
if (!tok) die("main: bad input");
read_state(aoc.input, start);
read_state(tok+1, end);
count = 0;
count_valid(start, end, 1, 1, 0, &count, check_pass_2);
aoc.answer = aprintf("%i", count);
aoc.solution = "628";
}
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