1 files changed, 62 insertions, 0 deletions

diff --git a/src/day15.cpp b/src/day15.cpp
new file mode 100644
index 0000000..905110f
--- /dev/null
+++ b/src/day15.cpp
@@ -0,0 +1,62 @@
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+using namespace std;
+
+string
+read_file(string_view filename)
+{
+        fstream input{ filename };
+        return { istreambuf_iterator<char>{ input }, istreambuf_iterator<char>{} };
+}
+
+inline string&
+rtrim(string& s, const char* t = " \t\n\r\f\v")
+{
+        s.erase(s.find_last_not_of(t) + 1);
+        return s;
+}
+
+vector<string>
+split(const string& line, char sep)
+{
+        vector<string> parts{};
+        stringstream   input{ line };
+
+        for ( string part; getline(input, part, sep); ) {
+                parts.emplace_back(rtrim(part));
+        }
+
+        return parts;
+}
+
+unsigned int
+calculate_hash(string_view str)
+{
+        unsigned int value = 0;
+        for ( auto chr: str ) {
+                value += static_cast<unsigned char>(chr);
+                value *= 17;
+        }
+        return value % 256;
+}
+
+void
+part1()
+{
+        const auto line  = read_file("data/day15.txt");
+        const auto parts = split(line, ',');
+        unsigned long value = 0;
+        for ( const auto& part: parts ) {
+                value += calculate_hash(part);
+        }
+        cout << value << endl;
+}
+
+int
+main()
+{
+        part1();
+}