aoc 2024, day 15, part 1, speedup

1 files changed, 12 insertions, 16 deletions

diff --git a/2024/src/day15.cpp b/2024/src/day15.cpp
index e11661e..5c2449b 100644
--- a/2024/src/day15.cpp
+++ b/2024/src/day15.cpp
@@ -1,6 +1,7 @@
 #include <fstream>
 #include <iostream>
 #include <map>
+#include <numeric>
 #include <optional>
 #include <set>
 #include <string>
@@ -50,6 +51,7 @@ read_file(string_view filename)
         return { room, boxes, movements, start };
 }
 
+/*
 void
 print(const room_type& room, const boxes_type& boxes, const pos_type& pos)
 {
@@ -72,6 +74,7 @@ print(const room_type& room, const boxes_type& boxes, const pos_type& pos)
         }
         cout << endl;
 }
+*/
 
 optional<boxes_type>
 can_move(const room_type& room, const boxes_type& boxes, pos_type start, pos_type direction) // NOLINT
@@ -114,26 +117,19 @@ part1(const puzzle_type& puzzle)
                         get<0>(start) += dx;
                         get<1>(start) += dy;
 
-                        boxes_type new_boxes;
-                        for ( const auto& box: boxes ) {
-                                if ( bitw->contains(box) ) {
-                                        const auto [x, y] = box;
-                                        new_boxes.emplace(x + dx, y + dy);
-                                        bitw->erase(box);
-                                }
-                                else {
-                                        new_boxes.insert(box);
-                                }
+                        for ( const auto& box: bitw.value() ) {
+                                boxes.erase(box);
+                        }
+
+                        for ( auto [x, y]: bitw.value() ) {
+                                boxes.emplace(x + dx, y + dy);
                         }
-                        boxes = new_boxes;
                 }
         }
 
-        size_t sum = 0;
-        for (const auto& [x, y]: boxes) {
-                sum += x + 100 * y;
-        }
-        cout << sum << endl;
+        cout << accumulate(boxes.begin(), boxes.end(), 0UL, [](auto init, const auto& box) {
+                return init + get<0>(box) + 100 * get<1>(box);
+        }) << endl;
 }
 
 int