Accepted solution to problem number 13 - conversion of Roman numerals to integers

13-roman-to-integer.cpp

@@ -0,0 +1,64 @@
+#include <string>
+#include <map>
+
+typedef std::map<std::string, unsigned long> RomanNumeral;
+
+class RomanToIntegerSolution {
+
+    private:
+        RomanNumeral numTable;
+
+    public:
+        int romanToInt(std::string s) {
+
+            unsigned long roman(0);
+            std::string remainder;
+            remainder.resize(s.length());
+
+            unsigned long singleRomanNumerals[255];
+
+            singleRomanNumerals['I'] = 1;
+            singleRomanNumerals['V'] = 5;
+            singleRomanNumerals['X'] = 10;
+            singleRomanNumerals['L'] = 50;
+            singleRomanNumerals['C'] = 100;
+            singleRomanNumerals['D'] = 500;
+            singleRomanNumerals['M'] = 1000;
+
+            numTable["IV"] = 4;
+            numTable["IX"] = 9;
+            numTable["XL"] = 40;
+            numTable["XC"] = 90;
+            numTable["CD"] = 400;
+            numTable["CM"] = 900;
+
+            auto len(s.length());
+            unsigned long j(0);
+            unsigned long i = 0;
+
+            for ( ; i < len-1; i++ ) {
+                char str[3];
+                str[0] = s[i];
+                str[1] = s[i+1];
+                str[2] = 0;
+
+                auto it(numTable.find(str));
+                if (it != numTable.end()) {
+                    roman += it->second;
+                    i++;
+                } else {
+                    remainder[j++] = s[i];
+                    remainder[j] = 0;
+                }
+            }
+            if ( i < len ) {
+                remainder[j++] = s[i];
+                remainder[j] = 0;
+            }
+            for (i = 0; (i < remainder.length()) && (remainder[i] != 0); i++) {
+                roman += singleRomanNumerals[remainder[i]];
+            }
+
+            return roman;
+        }
+};

main.cpp

@@ -3,6 +3,7 @@
 #include "1-two-sum.cpp"
 #include "2-add-two-numbers.cpp"
 #include "9-palindrome-number.cpp"
+#include "13-roman-to-integer.cpp"
 
 int main() {
     TwoSumSolution twoSumSolution;
@@ -56,5 +57,8 @@ int main() {
     PalindromeNumberSolution p;
     std::cout << "Is 1 palindrome? " << p.isPalindrome(1) << std::endl;
 
+    RomanToIntegerSolution r;
+    std::cout << "MCMXCIV = " << r.romanToInt("MCMXCIV") << std::endl;
+
     return 0;
 }