benutze sub-groups in der regex; kein sscanf() mehr

1 files changed, 6 insertions, 12 deletions

diff --git a/2024/src/day03.cpp b/2024/src/day03.cpp
index 5b6ec9e..bfbd781 100644
--- a/2024/src/day03.cpp
+++ b/2024/src/day03.cpp
@@ -15,14 +15,11 @@ read_file(string_view filename)
 void
 part1(const string& data)
 {
-        static const regex pattern(R"(mul\(\d{1,3},\d{1,3}\))");
+        static const regex pattern{ R"(mul\((\d{1,3}),(\d{1,3})\))" };
 
         long sum = 0;
-        for ( auto it = sregex_iterator(data.begin(), data.end(), pattern); it != sregex_iterator(); ++it ) {
-                long lhs = 0;
-                long rhs = 0;
-                sscanf(it->str().c_str(), "mul(%ld,%ld)", &lhs, &rhs);
-                sum += lhs * rhs;
+        for ( auto it = sregex_iterator{ data.begin(), data.end(), pattern }; it != sregex_iterator{}; ++it ) {
+                sum += stol((*it)[1]) * stol((*it)[2]);
         }
         cout << sum << endl;
 }
@@ -30,11 +27,11 @@ part1(const string& data)
 void
 part2(const string& data)
 {
-        static const regex pattern(R"(do\(\)|don't\(\)|mul\(\d{1,3},\d{1,3}\))");
+        static const regex pattern{ R"(do\(\)|don't\(\)|mul\((\d{1,3}),(\d{1,3})\))" };
 
         long sum   = 0;
         bool state = true;
-        for ( auto it = sregex_iterator(data.begin(), data.end(), pattern); it != sregex_iterator(); ++it ) {
+        for ( auto it = sregex_iterator{ data.begin(), data.end(), pattern }; it != sregex_iterator{}; ++it ) {
                 if ( it->str() == "do()" ) {
                         state = true;
                 }
@@ -42,10 +39,7 @@ part2(const string& data)
                         state = false;
                 }
                 else if ( state ) {
-                        long lhs = 0;
-                        long rhs = 0;
-                        sscanf(it->str().c_str(), "mul(%ld,%ld)", &lhs, &rhs);
-                        sum += lhs * rhs;
+                        sum += stol((*it)[1]) * stol((*it)[2]);
                 }
         }
         cout << sum << endl;