1 files changed, 6 insertions, 22 deletions

diff --git a/src/day09.cpp b/src/day09.cpp
index 1e9bde5..0019d05 100644
--- a/src/day09.cpp
+++ b/src/day09.cpp
@@ -28,7 +28,7 @@ read_ints(const string& line)
 
 template<typename T>
 T
-solve_rec_part1(const vector<T>& values)
+solve_rec(const vector<T>& values)
 {
         vector<T> differences;
 
@@ -37,7 +37,7 @@ solve_rec_part1(const vector<T>& values)
         }
         auto all_zeros = all_of(differences.begin(), differences.end(), [](T diff) { return diff == 0; });
         if ( !all_zeros ) {
-                return solve_rec_part1(differences) + values.back();
+                return solve_rec(differences) + values.back();
         }
         else {
                 return values.back();
@@ -51,35 +51,19 @@ part1()
 
         long sum = 0;
         for ( const auto& line: lines ) {
-                sum += solve_rec_part1(read_ints(line));
+                sum += solve_rec(read_ints(line));
         }
         cout << sum << endl;
 }
 
-template<typename T>
-T
-solve_rec_part2(const vector<T>& values)
-{
-        vector<T> differences;
-
-        for ( size_t idx = 1; idx < values.size(); ++idx ) {
-                differences.emplace_back(values[idx] - values[idx - 1]);
-        }
-        auto all_zeros = all_of(differences.begin(), differences.end(), [](T diff) { return diff == 0; });
-        if ( !all_zeros ) {
-                return values.front() - solve_rec_part2(differences);
-        }
-        else {
-                return values.front();
-        }
-}
-
 void
 part2()
 {
         long sum = 0;
         for ( const auto& line: read_file("data/day09.txt") ) {
-                sum += solve_rec_part2(read_ints(line));
+                auto values = read_ints(line);
+                reverse(values.begin(), values.end());
+                sum += solve_rec(values);
         }
         cout << sum << endl;
 }