1 files changed, 43 insertions, 1 deletions

diff --git a/2017/src/day01.cpp b/2017/src/day01.cpp
index 4a3fd99..f8297e7 100644
--- a/2017/src/day01.cpp
+++ b/2017/src/day01.cpp
@@ -1,9 +1,51 @@
+#include <filesystem>
+#include <fstream>
 #include <iostream>
+#include <string>
 
 using namespace std;
 
+namespace {
+
+string
+read_line(const filesystem::path& filename)
+{
+        ifstream file{ filename };
+        string   line;
+        getline(file, line);
+        return line;
+}
+
+long
+calculate(string_view captcha, size_t offset)
+{
+        long sum = 0;
+        for ( size_t i = 0; i != captcha.size(); ++i ) {
+                if ( captcha[i] == captcha[(i + offset) % captcha.size()] ) {
+                        sum += captcha[i] - '0';
+                }
+        }
+        return sum;
+}
+
+void
+part1(string_view captcha)
+{
+        cout << "Part1: " << calculate(captcha, 1) << '\n';
+}
+
+void
+part2(string_view captcha)
+{
+        cout << "Part2: " << calculate(captcha, captcha.size() / 2) << '\n';
+}
+
+} // namespace
+
 int
 main()
 {
-        cout << "Hallo Welt" << '\n';
+        auto captcha = read_line("data/day01.txt");
+        part1(captcha);
+        part2(captcha);
 }