Day 4

CMakeLists.txt

@@ -12,3 +12,4 @@ endif()
 add_executable(d1 "d1/main.cxx") 
 add_executable(d2 "d2/main.cxx") 
 add_executable(d3 "d3/main.cxx") 
+add_executable(d4 "d4/main.cxx") 

d4/main.cxx

@@ -0,0 +1,33 @@
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <string>
+
+int main()
+{
+  std::ifstream file{"../d4/input.txt"};
+
+  uint32_t pairs{0};
+
+  std::string line;
+  while (std::getline(file, line))
+  {
+    std::string fst{line.substr(0, line.find(','))}, snd{line.substr(line.find(',') + 1)};
+
+    fst = fst.replace(fst.find("-"), 1, " ");
+    snd = snd.replace(snd.find("-"), 1, " ");
+
+    uint32_t fl, fh, sl, sh;
+    std::stringstream fstSs(fst), sndSs(snd);
+
+    fstSs >> fl >> fh;
+    sndSs >> sl >> sh;
+
+    if (!(fh < sl || sh < fl))
+      pairs++;
+  }
+
+  std::cout << pairs << std::endl;
+
+  return 0;
+}