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Platy platy/fren :!platywave: Hello friend! :!marseysheepdog:  1yr ago (text post) 157 thread views #132457

Day 18 AoC: A nice break :marseybeanrelieved:

This one was very easy compared to the last two days

10
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Finally another problem that bruteforce chads can solve in few milliseconds! I had to imprecate a lot because of a stupid unsigned integer underflow (C++chads truly can't stop winning) and before founding it I implemented 2+1 counting methods plus a forth one plagiarized from Snakes, that's why I store two representations of the universe at the same time

:#marseyretardchad::#marseydrsneks::!#marseyretardchad:

![](/images/1671383813697684.webp)

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There's constexpr for compile time known constants instead of the preprocessor #define

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:#marseyhijab:

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Cleaned up per usual. For the actual live solve I had unrolled loops because I can type faster than I can think. Stuff like this:

if (c[0]+1,c[1],c[2]) in cubes: sides -= 1
if (c[0]-1,c[1],c[2]) in cubes: sides -= 1
if (c[0],c[1]+1,c[2]) in cubes: sides -= 1
if (c[0],c[1]-1,c[2]) in cubes: sides -= 1
if (c[0],c[1],c[2]+1) in cubes: sides -= 1
if (c[0],c[1],c[2]-1) in cubes: sides -= 1

![](/images/16713962212272782.webp)

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Pretty easy today. Part one as you would do it and part two as a bfs that will stop if it traverse into a cubes and counts +1 to the counter of sides facing the water.


#include <iostream>
#include <tuple>
#include <set>
#include <string>
#include <fstream>
#include <sstream>
#include <format>
#include <vector>
#include <queue>
#include <map>

struct coordinate {
	int x;
	int y;
	int z;

	coordinate operator+(const coordinate r) const {
		return {x + r.x, y + r.y, z + r.z};
	}

	auto operator<=>(const coordinate&) const = default;
};

typedef std::set<coordinate> set_type;

std::vector<coordinate> dirs{ { {0,0,1},{0,0,-1},{0,1,0},{0,-1,0},{1,0,0},{-1,0,0} } };

int count_neigbors(coordinate coord, const set_type& set) {
	int count{ 0 };
	for (auto dir : dirs) {
		if (set.contains(coord + dir)) count++;
	}
	return count;
}

int main()
{
	std::fstream file("input.txt");
	std::string buf;

	set_type cubes;

	int max_dimension{ INT_MIN };
	int min_dimension{ INT_MAX };

	while (std::getline(file, buf)) {
		int x, y, z;
		char c;
		std::istringstream iss( buf );
		iss >> x >> c >> y >> c >> z;
		max_dimension = std::max({ x, y, z, max_dimension });
		min_dimension = std::min({ x, y, z, min_dimension });
		cubes.insert({x,y,z});
	}
	int total{0};
	for (auto it = cubes.cbegin(); it != cubes.cend(); ++it) {
		total += 6 - count_neigbors(*it, cubes);
	}
	std::cout << "Part One: " << total << '\n';

	// We need to be able to "walk" around the entire cube area
	++max_dimension;
	--min_dimension;

	set_type explored;
	std::queue<coordinate> q;
	int result{ 0 };
	
	coordinate start { 0, 0, 0 };
	q.push(start);

	while (!q.empty()) {
		auto& cur = q.front();
		q.pop();
		if (explored.find(cur) != explored.end()) continue;
		explored.insert(cur);
		for (const auto& dir : dirs) {
			coordinate next = cur + dir;
			if (next.x > max_dimension || next.y > max_dimension || next.z > max_dimension ||
				next.x < min_dimension || next.y < min_dimension || next.z < min_dimension)
				continue;
			if (cubes.contains(next)) {
				result += 1;
			}
			else {
				q.push(next);
			}
		}
	} 
	std::cout << "Part Two " << result << '\n';
}
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I don't have enough spoons to read this shit

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Today's challenge gave me leeway to be lazy and retarded, so lazy and retarded I shall be.

foo = []
with open('day18_input.txt', 'r') as inp:
    foo = inp.read().split('\n')

cube_grid = [[[False for x in range(21)] for y in range(21)] for z in range(21)]
n = 0
for f in foo:
    f = [int(i) for i in f.split(',')]
    n_delta = 0
    for i in [[f[0]+1,f[1],f[2]],[f[0]-1,f[1],f[2]],[f[0],f[1]+1,f[2]],[f[0],f[1]-1,f[2]],[f[0],f[1],f[2]+1],[f[0],f[1],f[2]-1]]:
        if cube_grid[i[0]][i[1]][i[2]]:
            n_delta -= 1
        else:
            n_delta += 1
    cube_grid[f[0]][f[1]][f[2]] = True
    n += n_delta
print(n)

visited = [[[False for x in range(21)] for y in range(21)] for z in range(21)]
check = [[0,0,0]]
while(len(check) > 0):
    f = check[0]
    check = check[1:]
    for i in [[f[0]+1,f[1],f[2]],[f[0]-1,f[1],f[2]],[f[0],f[1]+1,f[2]],[f[0],f[1]-1,f[2]],[f[0],f[1],f[2]+1],[f[0],f[1],f[2]-1]]:
        if 20 >= i[0] >= 0 and 20 >= i[1] >= 0 and 20 >= i[2] >= 0 and not cube_grid[i[0]][i[1]][i[2]] and not visited[i[0]][i[1]][i[2]]:
            check.append(i)
            visited[i[0]][i[1]][i[2]] = True

for z in range(21):
    for y in range(21):
        for x in range(21):
            if not cube_grid[x][y][z] and not visited[x][y][z]:
                f = [x,y,z]
                for i in [[f[0]+1,f[1],f[2]],[f[0]-1,f[1],f[2]],[f[0],f[1]+1,f[2]],[f[0],f[1]-1,f[2]],[f[0],f[1],f[2]+1],[f[0],f[1],f[2]-1]]:
                    if 20 >= i[0] >= 0 and 20 >= i[1] >= 0 and 20 >= i[2] >= 0 and cube_grid[i[0]][i[1]][i[2]]:
                        n -= 1
print(n)
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Had to increase python's recursion limit to 15 000 :marseysweating:

![](/images/1671377039774784.webp)

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phew, that let me catch up from the day 16 frickery and day 17 tedium

![](/images/16713974879836175.webp)

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:#marseymormon:

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