Branch data     Line data    Source code

       1                 :             : #include <iostream>
       2                 :             : #include <fstream>
       3                 :             : #include <vector>
       4                 :             : #include <sstream>
       5                 :             : #include <ranges>
       6                 :             : #include <iterator>
       7                 :             : #include <cmath>
       8                 :             : using namespace std;
       9                 :             : 
      10                 :        1898 : bool isValid(const auto& nums, bool wrongSign, int skip = -1) {
      11   [ +  +  +  + ]:       10577 :   auto filtered = nums | views::filter([&nums, skip](const auto& e) { return skip < 0 || &e != &nums[skip]; });
      12                 :        1898 :   auto it = filtered.begin();
      13         [ +  + ]:        6460 :   for (auto prev = *it++, index = 1; it != filtered.end(); prev = *it++, ++index) {
      14   [ +  +  +  +  :        5883 :     if (auto diff = *it - prev; abs(diff) < 1 || abs(diff) > 3 || signbit(diff) == wrongSign) {
             +  +  +  + ]
      15   [ +  +  +  +  :        1321 :       return skip < 0 && (isValid(nums, wrongSign, index) || isValid(nums, wrongSign, index - 1));
                   +  + ]
      16                 :             :     }
      17                 :             :   }
      18                 :         577 :   return true;
      19                 :             : }
      20                 :             : 
      21                 :           2 : int main() {
      22                 :           2 :   ifstream file("input.txt");
      23         [ +  + ]:           2 :   if (!file) {
      24                 :           1 :     cerr << "Error: Could not open file 'input.txt'" << endl;
      25                 :           1 :     return 1;
      26                 :             :   }
      27                 :             : 
      28                 :           1 :   int validCount = 0;
      29                 :             : 
      30         [ +  + ]:        1001 :   for (string line; getline(file, line);) {
      31                 :        1000 :     istringstream iss(line);
      32                 :        2000 :     vector<int> nums{istream_iterator<int>(iss), {}};
      33                 :        1000 :     bool wrongSign = (signbit(nums[1] - nums[0]) + signbit(nums[2] - nums[1]) + signbit(nums[3] - nums[2])) < 2;
      34                 :        1000 :     validCount += isValid(nums, wrongSign);
      35                 :        1001 :   }
      36                 :             : 
      37                 :           1 :   cout << validCount << endl;
      38         [ +  + ]:           3 : }