154 lines
2.3 KiB
C++
154 lines
2.3 KiB
C++
#include <BAN/Vector.h>
|
|
|
|
#include <ctype.h>
|
|
#include <inttypes.h>
|
|
#include <stdio.h>
|
|
|
|
using i8 = int8_t;
|
|
using i16 = int16_t;
|
|
using i32 = int32_t;
|
|
using i64 = int64_t;
|
|
using isize = ssize_t;
|
|
|
|
using u8 = uint8_t;
|
|
using u16 = uint16_t;
|
|
using u32 = uint32_t;
|
|
using u64 = uint64_t;
|
|
using usize = size_t;
|
|
|
|
static BAN::Vector<u32> parse_input(FILE* fp)
|
|
{
|
|
BAN::Vector<u32> result;
|
|
|
|
u32 idx = 0;
|
|
|
|
char buffer[1024];
|
|
while (fgets(buffer, sizeof(buffer), fp))
|
|
{
|
|
usize len = strlen(buffer);
|
|
if (len > 0 && buffer[len - 1] == '\n')
|
|
len--;
|
|
|
|
for (usize i = 0; i < len; i++)
|
|
{
|
|
const u32 block_id = (idx % 2) ? 0xFFFFFFFF : idx / 2;
|
|
|
|
ASSERT(isdigit(buffer[i]));
|
|
for (i8 j = 0; j < buffer[i] - '0'; j++)
|
|
MUST(result.push_back(block_id));
|
|
|
|
idx++;
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
i64 part1(FILE* fp)
|
|
{
|
|
auto input = parse_input(fp);
|
|
|
|
usize l = 0;
|
|
usize r = input.size() - 1;
|
|
|
|
i64 result = 0;
|
|
|
|
while (l <= r)
|
|
{
|
|
if (input[l] != 0xFFFFFFFF)
|
|
{
|
|
result += input[l] * l;
|
|
l++;
|
|
continue;
|
|
}
|
|
|
|
while (l < r && input[r] == 0xFFFFFFFF)
|
|
r--;
|
|
|
|
if (l == r)
|
|
continue;
|
|
|
|
result += input[r] * l;
|
|
r--;
|
|
l++;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
i64 part2(FILE* fp)
|
|
{
|
|
auto input = parse_input(fp);
|
|
|
|
for (usize r = input.size(); r > 0;)
|
|
{
|
|
if (input[r - 1] == 0xFFFFFFFF)
|
|
{
|
|
r--;
|
|
continue;
|
|
}
|
|
|
|
const u32 id = input[r - 1];
|
|
|
|
usize rlen = 0;
|
|
while (r - rlen - 1 > 0 && input[r - rlen - 1] == id)
|
|
rlen++;
|
|
|
|
usize l = 0;
|
|
for (; l < r - rlen; l++)
|
|
{
|
|
if (input[l] != 0xFFFFFFFF)
|
|
continue;
|
|
|
|
usize llen = 1;
|
|
while (llen < rlen && input[l + llen] == 0xFFFFFFFF)
|
|
llen++;
|
|
|
|
if (llen == rlen)
|
|
break;
|
|
}
|
|
|
|
if (l < r - rlen)
|
|
{
|
|
for (usize i = 0; i < rlen; i++)
|
|
input[r - i - 1] = 0xFFFFFFFF;
|
|
for (usize i = 0; i < rlen; i++)
|
|
input[l + i] = id;
|
|
}
|
|
|
|
r -= rlen;
|
|
while (r > 0 && input[r - 1] == id)
|
|
r--;
|
|
}
|
|
|
|
i64 result = 0;
|
|
for (usize i = 0; i < input.size(); i++)
|
|
if (input[i] != 0xFFFFFFFF)
|
|
result += i * input[i];
|
|
|
|
return result;
|
|
}
|
|
|
|
int main(int argc, char** argv)
|
|
{
|
|
const char* file_path = "/usr/share/aoc2024/day9_input.txt";
|
|
|
|
if (argc >= 2)
|
|
file_path = argv[1];
|
|
|
|
FILE* fp = fopen(file_path, "r");
|
|
if (fp == nullptr)
|
|
{
|
|
perror("fopen");
|
|
return 1;
|
|
}
|
|
|
|
printf("part1: %" PRId64 "\n", part1(fp));
|
|
|
|
fseek(fp, 0, SEEK_SET);
|
|
|
|
printf("part2: %" PRId64 "\n", part2(fp));
|
|
|
|
fclose(fp);
|
|
}
|