Add problem 12.

1 files changed, 51 insertions, 0 deletions

diff --git a/cpp/12.cpp b/cpp/12.cpp
new file mode 100644
index 0000000..68eb4b4
--- /dev/null
+++ b/cpp/12.cpp
@@ -0,0 +1,51 @@
+#include <string>
+
+using std::string;
+
+const char *roman_digits = "IVXLCDM";
+
+class Solution
+{
+public:
+    string intToRoman(int num)
+    {
+        string result;
+
+        int current_digit_index = 0;
+
+        while (num != 0)
+        {
+            const int digit = num % 10;
+            if (digit == 9)
+            {
+                result += roman_digits[current_digit_index + 2];
+                result += roman_digits[current_digit_index];
+            }
+            else if (digit <= 8 && digit >= 5)
+            {
+                for (int i = 0; i < digit - 5; i++)
+                {
+                    result += roman_digits[current_digit_index];
+                }
+                result += roman_digits[current_digit_index + 1];
+            }
+            else if (digit == 4)
+            {
+                result += roman_digits[current_digit_index + 1];
+                result += roman_digits[current_digit_index];
+            }
+            else
+            {
+                for (int i = 0; i < digit; i++)
+                {
+                    result += roman_digits[current_digit_index];
+                }
+            }
+
+            num /= 10;
+            current_digit_index += 2;
+        }
+
+        return string(result.crbegin(), result.crend());
+    }
+};
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