Added day 6 (two programs. had to rewrite for the second problem). Added starter files.

2022/6/main.cpp

@@ -0,0 +1,56 @@
+#include <deque>
+#include <fstream>
+#include <iostream>
+#include <set>
+#include <string>
+#include <vector>
+
+bool Unique(const std::deque<char> &buf)
+{
+	std::set<char> s;
+	for(const char &ch : buf)
+		s.insert(ch);
+	return (s.size() == 4);
+}
+
+int main()
+{
+	std::ifstream ifs("data.txt");
+	if(!ifs.is_open())
+	{
+		std::cerr << "Missing data.txt." << std::endl;
+		return -1;
+	}
+
+	for(std::string line; std::getline(ifs, line); )
+	{
+		if(line == "")
+			continue;
+
+		std::deque<char> buf;
+
+		int idx = 0;
+		for(const char &ch : line)
+		{
+			++idx;
+			buf.push_back(ch);
+			if(buf.size() >= 4)
+			{
+				while(buf.size() > 4)
+					buf.pop_front();
+
+				if(Unique(buf))
+				{
+					std::cout << "At index " << idx << ": ";
+					for(const char &ch : buf)
+						std::cout << ch;
+					std::cout << std::endl;
+
+					break;
+				}
+			}
+		}
+	}
+
+	return 0;
+}