First star of 2022 #5.

2022/5/main.cpp

@@ -0,0 +1,99 @@
+#include <algorithm>
+#include <fstream>
+#include <iostream>
+#include <string>
+#include <vector>
+
+void DebugOutput(std::vector<std::vector<char>> &stacks)
+{
+	// DEBUG:
+	for(const auto &st : stacks)
+	{
+		std::cout << "Stack: " << std::endl;
+		for(const auto &ch : st)
+			std::cout << "[" << ch << "]" << std::endl;
+		std::cout <<  std::endl;
+	}
+}
+
+std::vector<std::string> SplitStr(std::string str, const std::string &delim)
+{
+	std::vector<std::string> rtn;
+
+	for(auto split = str.find(delim); split != std::string::npos; split = str.find(delim))
+	{
+		rtn.push_back(str.substr(0, split));
+		str = str.substr(split + delim.size()); // chop off beginning
+	}
+	if(str.size())
+		rtn.push_back(str);
+
+	return rtn;
+}
+
+int main()
+{
+	std::ifstream ifs("data.txt");
+	if(!ifs.is_open())
+	{
+		std::cerr << "Missing data.txt." << std::endl;
+		return -1;
+	}
+
+	std::vector<std::vector<char>> stacks;
+
+	// Step 1: Parse Starting Position
+	for(std::string line; std::getline(ifs, line); )
+	{
+		if(line == "")
+			break;
+
+		stacks.resize((line.size() + 1) / 4);
+		for(auto idx = 0; (idx * 4) < line.size(); ++idx)
+			if(line[1 + idx * 4] != ' ')
+				stacks[idx].push_back(line[1 + idx * 4]);
+	}
+
+	// Step 2: Clean up data:
+	for(auto &st : stacks)
+	{
+		// clear out last line of each, seeing as how they're just index numbers:
+		st.pop_back();
+		// reverse list since we parsed top to bottom and inserted backwards...
+		std::reverse(st.begin(), st.end());
+	}
+
+	// DebugOutput(stacks);
+
+	// Step 3: Parse Actions
+	for(std::string line; std::getline(ifs, line); )
+	{
+		if(line == "")
+			continue;
+
+		auto actions = SplitStr(line, " ");
+		if(actions.size() != 6)
+		{
+			std::cerr << "Data corrupt: " << line << std::endl;
+			exit(-1);
+		}
+
+		long amt = std::atoi(actions[1].c_str());
+		long from = std::atoi(actions[3].c_str()) - 1;
+		long to = std::atoi(actions[5].c_str()) - 1;
+
+		for(auto i = 0; i < amt; ++i)
+		{
+			stacks[to].push_back(stacks[from].back());
+			stacks[from].pop_back();
+		}
+	}
+
+	// DebugOutput(stacks);
+
+	for(const auto &st : stacks)
+		std::cout << st.back();
+	std::cout << std::endl;
+
+	return 0;
+}