Day 4 was MUCH easier than REGEX DAY 3.

2024-12-04 11:16:51 -05:00
parent c4d14c613d
commit 8fb1a7d95c
4 changed files with 321 additions and 0 deletions
--- a/2024/4/main.cpp
+++ b/2024/4/main.cpp
@@ -0,0 +1,169 @@
+#include <fstream>
+#include <iostream>
+#include <set>
+#include <sstream>
+#include <string>
+#include <vector>
+
+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::vector<std::vector<char>> game;
+
+	for(std::string line; std::getline(ifs, line); )
+	{
+		if(line == "")
+			continue;
+
+		// Add new row to fill out:
+		game.push_back({});
+
+		// for each value in the line:
+		for(const char &c : line)
+		{
+			// Fill out the row:
+			game.back().push_back(c);
+		}
+	}
+
+	// DEBUG:
+	// for(auto row : game)
+	// {
+	// 	for(auto c : row)
+	// 		std::cout << c;
+	// 	std::cout << std::endl;
+	// }
+
+	for(int y = 0; y < game.size(); ++y)
+	{
+		for(int x = 0; x < game[y].size(); ++x)
+		{
+			// right:
+			if(x + 3 < game[y].size())
+			{
+				if(game[y][x] == 'X' &&
+				   game[y][x+1] == 'M' &&
+				   game[y][x+2] == 'A' &&
+				   game[y][x+3] == 'S')
+					++total;
+			}
+
+			// down right:
+			if(x + 3 < game[y].size() &&
+			   y + 3 < game.size())
+			{
+				if(game[y][x] == 'X' &&
+				   game[y+1][x+1] == 'M' &&
+				   game[y+2][x+2] == 'A' &&
+				   game[y+3][x+3] == 'S')
+					++total;
+			}
+
+			// down:
+			if(y + 3 < game.size())
+			{
+				if(game[y][x] == 'X' &&
+				   game[y+1][x] == 'M' &&
+				   game[y+2][x] == 'A' &&
+				   game[y+3][x] == 'S')
+					++total;
+			}
+
+			// down left:
+			if(x - 3 >= 0 &&
+			   y + 3 < game.size())
+			{
+				if(game[y][x] == 'X' &&
+				   game[y+1][x-1] == 'M' &&
+				   game[y+2][x-2] == 'A' &&
+				   game[y+3][x-3] == 'S')
+					++total;
+			}
+
+			// left:
+			if(x - 3 >= 0)
+			{
+				if(game[y][x] == 'X' &&
+				   game[y][x-1] == 'M' &&
+				   game[y][x-2] == 'A' &&
+				   game[y][x-3] == 'S')
+					++total;
+			}
+
+			// up left:
+			if(x - 3 >= 0 &&
+			   y - 3 >= 0)
+			{
+				if(game[y][x] == 'X' &&
+				   game[y-1][x-1] == 'M' &&
+				   game[y-2][x-2] == 'A' &&
+				   game[y-3][x-3] == 'S')
+					++total;
+			}
+
+			// up:
+			if(y - 3 >= 0)
+			{
+				if(game[y][x] == 'X' &&
+				   game[y-1][x] == 'M' &&
+				   game[y-2][x] == 'A' &&
+				   game[y-3][x] == 'S')
+					++total;
+			}
+
+			// up right:
+			if(x + 3 < game[y].size() &&
+			   y - 3 >= 0)
+			{
+				if(game[y][x] == 'X' &&
+				   game[y-1][x+1] == 'M' &&
+				   game[y-2][x+2] == 'A' &&
+				   game[y-3][x+3] == 'S')
+					++total;
+			}
+		}
+	}
+
+	for(int y = 1; y < game.size() - 1; ++y)
+	{
+		for(int x = 1; x < game[y].size() - 1; ++x)
+		{
+			if(game[y][x] != 'A')
+				continue;
+
+			int good = 0;
+			// top left to bottom right
+			if((game[y-1][x-1] == 'M' &&
+			    game[y+1][x+1] == 'S')
+			   ||
+			   (game[y-1][x-1] == 'S' &&
+			    game[y+1][x+1] == 'M'))
+				++good;
+			// top right to bottom left
+			if((game[y-1][x+1] == 'M' &&
+			    game[y+1][x-1] == 'S')
+			   ||
+			   (game[y-1][x+1] == 'S' &&
+			    game[y+1][x-1] == 'M'))
+				++good;
+
+			if(good == 2)
+				++total_pt2;
+		}
+	}
+
+	std::cout << "    Total: " <<     total << std::endl;
+	std::cout << "PT2 Total: " << total_pt2 << std::endl;
+
+	return 0;
+}