diff options
Diffstat (limited to '2024')
| -rw-r--r-- | 2024/src/day07.cpp | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/2024/src/day07.cpp b/2024/src/day07.cpp new file mode 100644 index 0000000..9b16b76 --- /dev/null +++ b/2024/src/day07.cpp | |||
| @@ -0,0 +1,62 @@ | |||
| 1 | #include <fstream> | ||
| 2 | #include <iostream> | ||
| 3 | #include <sstream> | ||
| 4 | #include <string> | ||
| 5 | #include <tuple> | ||
| 6 | #include <vector> | ||
| 7 | using namespace std; | ||
| 8 | |||
| 9 | vector<tuple<long, vector<long>>> | ||
| 10 | read_file(string_view filename) | ||
| 11 | { | ||
| 12 | fstream input{ filename }; | ||
| 13 | |||
| 14 | vector<tuple<long, vector<long>>> data; | ||
| 15 | for ( string line; getline(input, line); ) { | ||
| 16 | auto pos = line.find(':'); | ||
| 17 | |||
| 18 | stringstream str{ line.substr(pos + 1) }; | ||
| 19 | data.emplace_back(stol(line.substr(0, pos)), vector<long>{ istream_iterator<long>{ str }, {} }); | ||
| 20 | } | ||
| 21 | return data; | ||
| 22 | } | ||
| 23 | |||
| 24 | bool | ||
| 25 | can_evaluated(long first, const vector<long>& values) | ||
| 26 | { | ||
| 27 | for ( unsigned long pattern = 0; pattern != (1U << (values.size() - 1)); ++pattern ) { | ||
| 28 | long result = values.at(0); | ||
| 29 | for ( size_t idx = 1; idx < values.size(); ++idx ) { | ||
| 30 | if ( (pattern & (1U << (idx - 1))) == 0 ) { | ||
| 31 | result += values.at(idx); | ||
| 32 | } | ||
| 33 | else { | ||
| 34 | result *= values.at(idx); | ||
| 35 | } | ||
| 36 | } | ||
| 37 | if ( first == result ) { | ||
| 38 | return true; | ||
| 39 | } | ||
| 40 | } | ||
| 41 | return false; | ||
| 42 | } | ||
| 43 | |||
| 44 | void | ||
| 45 | part1(const vector<tuple<long, vector<long>>>& data) | ||
| 46 | { | ||
| 47 | long sum = 0; | ||
| 48 | for ( const auto& [first, values]: data ) { | ||
| 49 | if ( can_evaluated(first, values) ) { | ||
| 50 | sum += first; | ||
| 51 | } | ||
| 52 | } | ||
| 53 | cout << sum << endl; | ||
| 54 | } | ||
| 55 | |||
| 56 | int | ||
| 57 | main() | ||
| 58 | { | ||
| 59 | auto data = read_file("data/day07.txt"); | ||
| 60 | |||
| 61 | part1(data); | ||
| 62 | } | ||
