1 files changed, 38 insertions, 0 deletions
diff --git a/store/works/life/chuanzhi-cup/practice-contest/3.cpp b/store/works/life/chuanzhi-cup/practice-contest/3.cpp
new file mode 100644
index 0000000..1f79723
--- /dev/null
+++ b/store/works/life/chuanzhi-cup/practice-contest/3.cpp
@@ -0,0 +1,38 @@
+#include <cmath>
+#include <iomanip>
+#include <iostream>
+#include <regex>
+#include <string>
+
+int main() {
+  std::string input;
+  std::getline(std::cin, input);
+
+  std::regex reg(R"aaa((\d+)([GMK]?B)=\?([GMK]?B))aaa");
+  std::smatch match;
+  std::regex_match(input, match, reg);
+
+  std::string original_number_str = match[1].str();
+  std::string original_unit = match[2].str();
+  std::string target_unit = match[3].str();
+
+  double original_number = std::stod(original_number_str);
+
+  auto to_ratio = [](const std::string s) -> double {
+    if (s.size() == 1)
+      return 1;
+    if (s[0] == 'G')
+      return std::pow(2, 30);
+    if (s[0] == 'M')
+      return std::pow(2, 20);
+    return std::pow(2, 10);
+  };
+
+  double original_ratio = to_ratio(original_unit);
+  double target_ratio = to_ratio(target_unit);
+
+  std::cout << std::fixed << std::setprecision(6)
+            << (original_number * original_ratio / target_ratio);
+
+  return 0;
+}