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day10
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@JellevanKraaij
JellevanKraaij committed Dec 10, 2023
1 parent 6661609 commit bc9134e
Showing 1 changed file with 79 additions and 22 deletions.
101 changes: 79 additions & 22 deletions day10/main.cpp
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
#include <algorithm>
#include <fstream>
#include <iostream>
#include <map>
#include <sstream>
#include <string>
#include <unordered_map>
Expand All @@ -10,15 +11,22 @@

using namespace std;

enum class Tile {
GROUND = '.',
VERTICAL = '|',
HORIZONTAL = '-',
BEND_NE = 'L',
BEND_NW = 'J',
BEND_SW = '7',
BEND_SE = 'F',
START = 'S',
class Tile {
public:
enum TileType {
GROUND = '.',
VERTICAL = '|',
HORIZONTAL = '-',
BEND_NE = 'L',
BEND_NW = 'J',
BEND_SW = '7',
BEND_SE = 'F',
START = 'S',
};
TileType type;
Tile(TileType type) : type(type) {}
bool isPartOfPath = false;
bool isBend() { return type == Tile::BEND_NE || type == Tile::BEND_NW || type == Tile::BEND_SW || type == Tile::BEND_SE; }
};

int main(int argc, char **argv) {
Expand All @@ -38,13 +46,13 @@ int main(int argc, char **argv) {
vector<vector<Tile>> map;
while (getline(inputFile, line)) {
vector<Tile> row;
transform(line.begin(), line.end(), back_inserter(row), [](char c) { return static_cast<Tile>(c); });
transform(line.begin(), line.end(), back_inserter(row), [](char c) { return static_cast<Tile::TileType>(c); });
map.push_back(row);
}

Vec2 startLocation;
for (auto it = map.begin(); it != map.end(); ++it) {
auto res = find(it->begin(), it->end(), Tile::START);
auto res = find_if(it->begin(), it->end(), [](Tile t) { return t.type == Tile::START; });
if (res != it->end()) {
startLocation[0] = distance(map.begin(), it);
startLocation[1] = distance(it->begin(), res);
Expand All @@ -53,35 +61,36 @@ int main(int argc, char **argv) {
}
}

static const array<pair<Vec2, vector<Tile>>, 4> directions = {{{Vec2{0, 1}, {Tile::HORIZONTAL, Tile::BEND_SW, Tile::BEND_NW}},
{Vec2{0, -1}, {Tile::HORIZONTAL, Tile::BEND_SE, Tile::BEND_NE}},
{Vec2{1, 0}, {Tile::VERTICAL, Tile::BEND_NW, Tile::BEND_NE}},
{Vec2{-1, 0}, {Tile::VERTICAL, Tile::BEND_SW, Tile::BEND_SE}}}};
static const array<pair<Vec2, vector<Tile::TileType>>, 4> directions = {{{Vec2{0, 1}, {Tile::HORIZONTAL, Tile::BEND_SW, Tile::BEND_NW}},
{Vec2{0, -1}, {Tile::HORIZONTAL, Tile::BEND_SE, Tile::BEND_NE}},
{Vec2{1, 0}, {Tile::VERTICAL, Tile::BEND_NW, Tile::BEND_NE}},
{Vec2{-1, 0}, {Tile::VERTICAL, Tile::BEND_SW, Tile::BEND_SE}}}};
Vec2 startDirection;
for (auto &direction : directions) {
Vec2 testLocation = startLocation + direction.first;
if (testLocation[0] < 0 || testLocation[0] >= map.size() || testLocation[1] < 0 || testLocation[1] >= map[testLocation[0]].size()) {
continue;
}
if (find(direction.second.begin(), direction.second.end(), map[testLocation[0]][testLocation[1]]) != direction.second.end()) {
if (find(direction.second.begin(), direction.second.end(), map[testLocation[0]][testLocation[1]].type) != direction.second.end()) {
startDirection = direction.first;
break;
}
}

static const unordered_map<Tile, pair<Vec2, Vec2>> tileDirections = {{Tile::BEND_NE, {{-1, 0}, {0, 1}}}, {Tile::BEND_NW, {{0, -1}, {-1, 0}}},
{Tile::BEND_SW, {{1, 0}, {0, -1}}}, {Tile::BEND_SE, {{0, 1}, {1, 0}}},
{Tile::HORIZONTAL, {{0, 1}, {0, -1}}}, {Tile::VERTICAL, {{1, 0}, {-1, 0}}}};
static const unordered_map<Tile::TileType, pair<Vec2, Vec2>> tileDirections = {
{Tile::BEND_NE, {{-1, 0}, {0, 1}}}, {Tile::BEND_NW, {{0, -1}, {-1, 0}}}, {Tile::BEND_SW, {{1, 0}, {0, -1}}},
{Tile::BEND_SE, {{0, 1}, {1, 0}}}, {Tile::HORIZONTAL, {{0, 1}, {0, -1}}}, {Tile::VERTICAL, {{1, 0}, {-1, 0}}}};
Vec2 currentLocation = startLocation + startDirection;
Vec2 currentDirection = startDirection;
int steps = 0;

while (true) {
steps++;
if (map[currentLocation[0]][currentLocation[1]] == Tile::START) {
map[currentLocation[0]][currentLocation[1]].isPartOfPath = true;
if (map[currentLocation[0]][currentLocation[1]].type == Tile::START) {
break;
}
pair<Vec2, Vec2> direction = tileDirections.at(map[currentLocation[0]][currentLocation[1]]);
pair<Vec2, Vec2> direction = tileDirections.at(map[currentLocation[0]][currentLocation[1]].type);
if (currentDirection == inverse(direction.first)) {
currentDirection = direction.second;
} else {
Expand All @@ -90,5 +99,53 @@ int main(int argc, char **argv) {
currentLocation = currentLocation + currentDirection;
}
cout << "Steps: " << steps << endl;
cout << "Result: " << steps / 2 << endl;

static const std::map<pair<Vec2, Vec2>, Tile::TileType> convertStart = {
{{{0, 1}, {0, -1}}, Tile::HORIZONTAL}, {{{0, -1}, {0, 1}}, Tile::HORIZONTAL}, {{{1, 0}, {-1, 0}}, Tile::VERTICAL},
{{{-1, 0}, {1, 0}}, Tile::VERTICAL}, {{{0, 1}, {1, 0}}, Tile::BEND_SW}, {{{1, 0}, {0, 1}}, Tile::BEND_SW},
{{{0, -1}, {1, 0}}, Tile::BEND_SE}, {{{1, 0}, {0, -1}}, Tile::BEND_SE}, {{{0, -1}, {-1, 0}}, Tile::BEND_NE},
{{{-1, 0}, {0, -1}}, Tile::BEND_NE}, {{{0, 1}, {-1, 0}}, Tile::BEND_NW}, {{{-1, 0}, {0, 1}}, Tile::BEND_NW},
};
map[startLocation[0]][startLocation[1]].type = convertStart.at(make_pair(startDirection, inverse(currentDirection)));

cout << "Start value: " << static_cast<char>(map[startLocation[0]][startLocation[1]].type) << endl;

enum Direction { UP, DOWN };

unordered_map<Tile::TileType, Direction> bendDirections = {
{Tile::BEND_NE, UP}, {Tile::BEND_NW, UP}, {Tile::BEND_SW, DOWN}, {Tile::BEND_SE, DOWN}};

int total = 0;
for (auto &row : map) {
bool insidePath = false;
bool encounteredBend = false;
Direction lastDir;
for (auto &tile : row) {
if (tile.isPartOfPath) {
if (tile.type == Tile::VERTICAL)
insidePath = !insidePath;
else if (tile.isBend()) {
if (!encounteredBend) {
encounteredBend = true;
lastDir = bendDirections.at(tile.type);
} else {
if (lastDir != bendDirections.at(tile.type))
insidePath = !insidePath;
encounteredBend = false;
}
}
}

if (insidePath && !tile.isPartOfPath) {
cout << 'I';
total++;
} else {
cout << static_cast<char>(tile.type);
}
}
cout << endl;
}

cout << "Result 1: " << steps / 2 << endl;
cout << "Result 2: " << total << endl;
}

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