Day 6 Part 1.

2024/6/main.cpp

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+#include <algorithm>
+#include <fstream>
+#include <iostream>
+#include <map>
+#include <set>
+#include <sstream>
+#include <string>
+#include <unistd.h>
+#include <vector>
+
+struct Position {
+	// NOTE(dev): Could do enum empty/reached/blocked, but I'm not interested.
+	bool blocked = false;
+	bool reached = false;
+};
+
+enum Direction {
+	UP = 0,
+	RIGHT,
+	DOWN,
+	LEFT
+};
+
+struct Player {
+	std::pair<int, int> location;
+	Direction direction = Direction::UP;
+};
+
+int main()
+{
+	const std::string filename = "data.txt";
+	std::ifstream ifs(filename);
+	if(!ifs.is_open())
+	{
+		std::cerr << "Missing " << filename << "." << std::endl;
+		return -1;
+	}
+
+	unsigned long total = 0;
+	unsigned long total_pt2 = 0;
+
+	std::map<std::pair<int, int>, Position> level;
+	Player player;
+
+	int max_x = 0;
+	int max_y = 0;
+	bool first_row = true;
+	int y = 0;
+
+	auto DebugPrint = [&]()
+	{
+		std::cout << std::endl;
+		for(auto y = 0; y < max_y; ++y)
+		{
+			for(auto x = 0; x < max_x; ++x)
+			{
+				if(player.location.first == x && player.location.second == y)
+				{
+					switch(player.direction)
+					{
+					case Direction::UP:
+						std::cout << "^";
+						break;
+					case Direction::RIGHT:
+						std::cout << ">";
+						break;
+					case Direction::DOWN:
+						std::cout << "v";
+						break;
+					case Direction::LEFT:
+						std::cout << "<";
+						break;
+					};
+				}
+				else
+				{
+					const auto &pos = level[{x, y}];
+					if(pos.reached)
+						std::cout << "X";
+					else if(pos.blocked)
+						std::cout << "#";
+					else
+						std::cout << ".";
+				}
+			}
+			std::cout << std::endl;
+		}
+	};
+
+	// Parse Input
+	for(std::string line; std::getline(ifs, line); )
+	{
+		if(line == "")
+			continue;
+
+		int x = 0;
+		for(const char &value : line)
+		{
+			Position pos;
+			if(value == '#')
+				pos.blocked = true;
+			if(value == '^') // always up?
+			{
+				pos.reached = true;
+				player.location = {x, y};
+			}
+
+			level[{x, y}] = pos;
+
+			++x;
+		}
+		if(first_row)
+		{
+			max_x = x;
+			first_row = false;
+		}
+		++y;
+	}
+	max_y = y;
+
+	// DEBUG:
+	DebugPrint();
+
+	std::cout << std::endl;
+
+	// while(player.location.first >= 0 && player.location.first < max_x &&
+	//       player.location.second >= 0 && player.location.second < max_y)
+	while(true)
+	{
+		std::pair<int, int> next_location = player.location;
+		switch(player.direction)
+		{
+		case Direction::UP:
+			--next_location.second;
+			break;
+		case Direction::RIGHT:
+			++next_location.first;
+			break;
+		case Direction::DOWN:
+			++next_location.second;
+			break;
+		case Direction::LEFT:
+			--next_location.first;
+			break;
+		};
+
+		if(!level.contains(next_location))
+		{
+			player.location = next_location;
+			break;
+		}
+		if(level[next_location].blocked)
+			player.direction = static_cast<Direction>(((int(player.direction)) + 1) % 4);
+		else
+		{
+			level[next_location].reached = true;
+			player.location = next_location;
+			// DebugPrint();
+			// usleep(20000);
+		}
+	}
+
+	DebugPrint();
+
+	for(auto y = 0; y < max_y; ++y)
+		for(auto x = 0; x < max_x; ++x)
+			if(level[{x,y}].reached)
+				++total;
+
+	std::cout << std::endl;
+	std::cout << "    Total: " <<     total << std::endl;
+	std::cout << "PT2 Total: " << total_pt2 << std::endl;
+
+	return 0;
+}