Initial commit

2020/puzzle-10-01.cc

@@ -0,0 +1,32 @@
+#include <algorithm>
+#include <array>
+#include <cassert>
+#include <iostream>
+#include <list>
+#include <map>
+#include <regex>
+#include <string>
+
+using Jolt = unsigned long;
+
+int main(int argc, char **argv) {
+  std::vector<Jolt> jolts;
+  for (std::string line; std::getline(std::cin, line);) {
+    jolts.push_back(std::stoul(line));
+  }
+
+  std::sort(jolts.begin(), jolts.end());
+  std::array<unsigned, 4> gaps = {};
+
+  Jolt last = 0;
+  for (auto j : jolts) {
+    ++gaps[j - last];
+    last = j;
+  }
+  // and the gap to our voltage
+  ++gaps[3];
+
+  std::cout << gaps[1] << " * " << gaps[3] << " = " << gaps[1] * gaps[3]
+            << "\n";
+  return 0;
+}