1 files changed, 64 insertions, 69 deletions

diff --git a/2024/src/day10.cpp b/2024/src/day10.cpp
index 58b797f..73e4f92 100644
--- a/2024/src/day10.cpp
+++ b/2024/src/day10.cpp
@@ -1,6 +1,7 @@
 #include <fstream>
 #include <iostream>
 #include <map>
+#include <numeric>
 #include <queue>
 #include <set>
 #include <string>
@@ -33,42 +34,8 @@ neighbors(pos_type pos)
         return { { x - 1, y }, { x, y - 1 }, { x + 1, y }, { x, y + 1 } };
 }
 
-size_t
-bfs(const map<pos_type, int>& data, pos_type start_pos)
-{
-        size_t peaks = 0;
-
-        set<pos_type>   seen;
-        queue<pos_type> queue;
-
-        queue.emplace(start_pos);
-        seen.emplace(start_pos);
-
-        while ( !queue.empty() ) {
-                auto pos = queue.front();
-                queue.pop();
-
-                if ( data.at(pos) == 9 ) {
-                        ++peaks;
-                        continue;
-                }
-
-                for ( const auto& neighbor: neighbors(pos) ) {
-                        if ( !data.contains(neighbor) ||
-                             seen.contains(neighbor) ||
-                             data.at(neighbor) != data.at(pos) + 1 ) {
-                                continue;
-                        }
-
-                        queue.emplace(neighbor);
-                        seen.insert(neighbor);
-                }
-        }
-        return peaks;
-}
-
-void
-part1(const map<pos_type, int>& data)
+vector<pos_type>
+get_starts(const map<pos_type, int>& data)
 {
         vector<pos_type> starts;
         for ( const auto& [pos, value]: data ) {
@@ -76,59 +43,87 @@ part1(const map<pos_type, int>& data)
                         starts.push_back(pos);
                 }
         }
-
-        size_t sum = 0;
-        for ( const auto& start: starts ) {
-                sum += bfs(data, start);
-        }
-        cout << sum << endl;
+        return starts;
 }
 
+template<typename BFS>
 size_t
-bfs2(const map<pos_type, int>& data, pos_type start_pos)
+solve(const map<pos_type, int>& data, BFS bfs)
 {
-        size_t paths = 0;
+        auto starts = get_starts(data);
+        return accumulate(starts.begin(), starts.end(), 0U, [&](auto init, auto start) { return init + bfs(data, start); });
+}
 
-        queue<pos_type> queue;
+void
+part1(const map<pos_type, int>& data)
+{
+        auto bfs = [](const map<pos_type, int>& data, pos_type start_pos) -> size_t {
+                size_t score = 0;
 
-        queue.push(start_pos);
+                set<pos_type>   seen;
+                queue<pos_type> queue;
 
-        while ( !queue.empty() ) {
-                auto pos = queue.front();
-                queue.pop();
+                queue.emplace(start_pos);
+                seen.emplace(start_pos);
 
-                if ( data.at(pos) == 9 ) {
-                        ++paths;
-                        continue;
-                }
+                while ( !queue.empty() ) {
+                        auto pos = queue.front();
+                        queue.pop();
 
-                for ( const auto& neighbor: neighbors(pos) ) {
-                        if ( !data.contains(neighbor) ||
-                             data.at(neighbor) != data.at(pos) + 1 ) {
+                        if ( data.at(pos) == 9 ) {
+                                ++score;
                                 continue;
                         }
 
-                        queue.emplace(neighbor);
+                        for ( const auto& neighbor: neighbors(pos) ) {
+                                if ( !data.contains(neighbor) ||
+                                     seen.contains(neighbor) ||
+                                     data.at(neighbor) != data.at(pos) + 1 ) {
+                                        continue;
+                                }
+
+                                queue.emplace(neighbor);
+                                seen.insert(neighbor);
+                        }
                 }
-        }
-        return paths;
+                return score;
+        };
+
+        cout << solve(data, bfs) << endl;
 }
 
 void
 part2(const map<pos_type, int>& data)
 {
-        vector<pos_type> starts;
-        for ( const auto& [pos, value]: data ) {
-                if ( value == 0 ) {
-                        starts.push_back(pos);
+        auto bfs = [](const map<pos_type, int>& data, pos_type start_pos) -> size_t {
+                size_t score = 0;
+
+                queue<pos_type> queue;
+
+                queue.push(start_pos);
+
+                while ( !queue.empty() ) {
+                        auto pos = queue.front();
+                        queue.pop();
+
+                        if ( data.at(pos) == 9 ) {
+                                ++score;
+                                continue;
+                        }
+
+                        for ( const auto& neighbor: neighbors(pos) ) {
+                                if ( !data.contains(neighbor) ||
+                                     data.at(neighbor) != data.at(pos) + 1 ) {
+                                        continue;
+                                }
+
+                                queue.emplace(neighbor);
+                        }
                 }
-        }
+                return score;
+        };
 
-        size_t sum = 0;
-        for ( const auto& start: starts ) {
-                sum += bfs2(data, start);
-        }
-        cout << sum << endl;
+        cout << solve(data, bfs) << endl;
 }
 
 int