2

Author: gogsbread

Diff for: cpp/2.cpp

@@ -0,0 +1,42 @@
+#include "common.h"
+
+namespace {
+long p1(const auto &input) {
+  std::unordered_map<std::string, std::string> wins{{"AY", "Y"}, {"AZ", "A"},
+                                                    {"BX", "B"}, {"BZ", "Z"},
+                                                    {"CX", "X"}, {"CY", "C"}};
+  long s{0};
+  for (const auto &l : input) {
+    std::string o, p;
+    std::istringstream{l} >> o >> p;
+    s += p[0] - 'W';
+    if (const auto &w = wins.find(o + p); w != wins.end()) {
+      s += (w->second == o) ? 0 : 6;
+    } else {
+      s += 3;
+    }
+  }
+  return s;
+}
+
+long p2(const auto &input) {
+  std::unordered_map<std::string, int> plays{
+      {"AX", 3 + 0}, {"AY", 1 + 3}, {"AZ", 2 + 6}, {"BX", 1 + 0}, {"BY", 2 + 3},
+      {"BZ", 3 + 6}, {"CX", 2 + 0}, {"CY", 3 + 3}, {"CZ", 1 + 6}};
+  long s{0};
+  for (const auto &l : input) {
+    std::string o, w;
+    std::istringstream{l} >> o >> w;
+    if (const auto &p = plays.at(o + w)) {
+      s += p;
+    }
+  }
+  return s;
+}
+} // namespace
+
+int main() {
+  const auto &input = gb::advent2021::readIn();
+  gb::advent2021::writeOut(std::to_string(p1(input)));
+  gb::advent2021::writeOut(std::to_string(p2(input)));
+}

Diff for: cpp/meson.build

@@ -6,9 +6,9 @@ executable('1',
     '1.cpp',
     dependencies: [])
 
-# executable('2',
-#     '2.cpp',
-#     dependencies: [])
+executable('2',
+    '2.cpp',
+    dependencies: [])
 
 # executable('3',
 #     '3.cpp',