WIP

2024/2/main_pt2.cpp

@@ -5,6 +5,8 @@
 #include <string>
 #include <vector>
 
+bool GroupSafe(const std::vector<long> &group);
+
 int main()
 {
 	std::ifstream ifs("data.txt");
@@ -41,15 +43,104 @@ int main()
 	}
 
 	// DEBUG:
-	for(auto row : data)
+	// for(auto row : data)
+	// {
+	// 	for(auto col : row)
+	// 		std::cout << col << " ";
+	// 	std::cout << std::endl;
+	// }
+
+	for(auto group : data)
 	{
-		for(auto col : row)
+		switch(group.size())
-			std::cout << col << ", ";
+		{
+		case 0:
+			// Go to next line
+			continue;
+			break;
+		case 1:
+			// Can't be increasing or decreasing because it's the only one, so I guess safe?
+			++total;
+			++total_pt2;
+			continue;
+			break;
+		};
+
+		bool safe = true;
+
+		if(GroupSafe(group))
+			++total;
+		else
+		{
+			bool re_safe = false;
+			for(auto i = 0; i < group.size(); ++i)
+			{
+				std::vector<long> check;
+				if(i != 0)
+					check = { group.begin(), group.begin() + i - 1 };
+				if(i < group.size() - 1)
+					check.insert(check.end(), group.begin() + i + 1, group.end());
+				if(GroupSafe(check))
+				{
+					re_safe = true;
+					++total_pt2;
+					break;
+				}
+			}
+			if(!re_safe)
+			{
+				std::cout << "Bad: ";
+				for(auto val : group)
+					std::cout << val << " ";
 				std::cout << std::endl;
 			}
-
+		}
+	}
 	std::cout << "    Total: " << total << std::endl;
-	std::cout << "PT2 Total: " << total_pt2 << std::endl;
+	std::cout << "PT2 Total: " << total + total_pt2 << std::endl;
 
 	return 0;
 }
+
+
+bool GroupSafe(const std::vector<long> &group)
+{
+	bool increasing = false;
+	for(auto i = 0; i < group.size() - 1; ++i)
+	{
+		if(group[i] == group[i+1])
+			continue;
+		increasing = group[i] < group[i+1];
+		break;
+	}
+
+	bool safe = true;
+	int *last = nullptr;
+	for(auto i = 0; i < group.size(); ++i)
+	{
+		auto next = group[i];
+
+		if(!last)
+		{
+			last = new int(next);
+			continue;
+		}
+
+		if(increasing &&
+		   (next - *last < 1 || next - *last > 3))
+			safe = false;
+		else if(!increasing &&
+		        (next - *last < -3 || next - *last > -1))
+			safe = false;
+
+		if(!safe)
+			break;
+
+		*last = next;
+	}
+
+	if(last)
+		delete last, last = nullptr;
+
+	return safe;
+}