1 files changed, 38 insertions, 49 deletions

diff --git a/2024/src/day24.cpp b/2024/src/day24.cpp
index 3f252a1..c2bd505 100644
--- a/2024/src/day24.cpp
+++ b/2024/src/day24.cpp
@@ -114,15 +114,6 @@ part1(const tuple<map<string, unsigned long>, map<string, tuple<string, string,
         cout << value << endl;
 }
 
-string
-make_wire(char chr, unsigned long num)
-{
-        static const size_t  MAX_LEN = 10;
-        array<char, MAX_LEN> tmp{};
-        snprintf(tmp.data(), tmp.size(), "%c%02lu", chr, num); // NOLINT
-        return tmp.data();
-}
-
 class RippleCarryAdder {
 public:
         explicit RippleCarryAdder(const tuple<map<string, unsigned long>, map<string, tuple<string, string, string>>>& data)
@@ -131,12 +122,6 @@ public:
         {
         }
 
-        RippleCarryAdder(const map<string, tuple<string, string, string>>& deps, unsigned long x_value, unsigned long y_value)
-            : deps_(deps)
-        {
-                build_inputs(x_value, y_value);
-        }
-
         void swap_wire(const string& lhs, const string& rhs)
         {
                 swap(deps_.at(lhs), deps_.at(rhs));
@@ -197,6 +182,14 @@ public:
         }
 
 private:
+        static string make_wire(char chr, unsigned long num)
+        {
+                static const size_t  MAX_LEN = 10;
+                array<char, MAX_LEN> tmp{};
+                snprintf(tmp.data(), tmp.size(), "%c%02lu", chr, num); // NOLINT
+                return tmp.data();
+        }
+
         void build_inputs(unsigned long x_value, unsigned long y_value)
         {
                 inputs_.clear();
@@ -269,54 +262,50 @@ part2(const tuple<map<string, unsigned long>, map<string, tuple<string, string,
         set<string> solution;
 
         for ( auto bit = 0UL; bit != MAX_BITS; ++bit ) {
-                const auto x_value = 1UL << bit; // (1UL << (bit+1)) - 1;
-                const auto y_value = 0UL << bit;
+                const auto x_value = 1UL << bit;
+                const auto y_value = 0UL;
 
                 if ( !rca.eval_z(x_value, y_value) ) {
                         return;
                 }
 
                 const auto failed_bits = rca.test(x_value, y_value);
-                if ( !failed_bits.empty() ) {
-                        set<string> candidates;
-                        for ( const auto& wire: failed_bits ) {
-                                rca.collect(wire, candidates);
-                        }
+                if ( failed_bits.empty() ) {
+                        continue;
+                }
 
-                        const vector<string> foo{ candidates.begin(), candidates.end() };
+                set<string> unique_candidates;
+                for ( const auto& wire: failed_bits ) {
+                        rca.collect(wire, unique_candidates);
+                }
 
-                        for ( auto i = foo.begin(); i != foo.end(); ++i ) {
-                                for ( auto j = i + 1; j != foo.end(); ++j ) {
-                                        auto do_test = [&](unsigned long lhs, unsigned long rhs) -> bool {
-                                                RippleCarryAdder rca_tester{ data };
+                const vector<string> candidates{ unique_candidates.begin(), unique_candidates.end() };
 
-                                                rca_tester.swap_wire(*i, *j);
+                for ( auto i = candidates.begin(); i != candidates.end(); ++i ) {
+                        for ( auto j = i + 1; j != candidates.end(); ++j ) {
+                                auto do_test = [&](const tuple<unsigned long, unsigned long>& test_value) -> bool {
+                                        const auto [lhs, rhs] = test_value;
 
-                                                if ( !rca_tester.eval_z(lhs, rhs) ) {
-                                                        return false;
-                                                }
-                                                return rca_tester.test(lhs, rhs).empty();
-                                        };
+                                        RippleCarryAdder rca_tester{ data };
 
-                                        if ( do_test(x_value, y_value) ) {
-                                                const auto x_value2 = 7UL << (bit - 1);
-                                                const auto y_value2 = 3UL << (bit - 1);
+                                        rca_tester.swap_wire(*i, *j);
 
-                                                if ( do_test(x_value2, y_value2) ) {
-                                                        const auto x_value3 = 1UL << bit;
-                                                        const auto y_value3 = 1UL << bit;
+                                        if ( !rca_tester.eval_z(lhs, rhs) ) {
+                                                return false;
+                                        }
+                                        return rca_tester.test(lhs, rhs).empty();
+                                };
 
-                                                        if ( do_test(x_value3, y_value3) ) {
-                                                                const auto x_value4 = 5UL << (bit - 1);
-                                                                const auto y_value4 = 3UL << (bit - 1);
+                                const vector<tuple<unsigned long, unsigned long>> test_values = {
+                                        { x_value, y_value },
+                                        { 7UL << (bit - 1), 3UL << (bit - 1) },
+                                        { 1UL << bit, 1UL << bit },
+                                        { 5UL << (bit - 1), 3UL << (bit - 1) }
+                                };
 
-                                                                if ( do_test(x_value4, y_value4) ) {
-                                                                        solution.insert(*i);
-                                                                        solution.insert(*j);
-                                                                }
-                                                        }
-                                                }
-                                        }
+                                if ( ranges::all_of(test_values, do_test) ) {
+                                        solution.insert(*i);
+                                        solution.insert(*j);
                                 }
                         }
                 }