3

Author: kedebug

IntegertoRoman/IntegertoRoman.cpp

@@ -0,0 +1,40 @@
+class Solution {
+public:
+    string intToRoman(int num) {
+        // Start typing your C/C++ solution below
+        // DO NOT write int main() function    
+        char symbol[] = {'I', 'V', 'X', 'L','C', 'D', 'M'};
+        string result;
+        int base = 1000;
+        int d = 6;
+        while (num) {
+            int digit = num / base;
+            appendRoman(digit, result, symbol + d);
+            d -= 2;
+            num %= base;
+            base /= 10;
+        }
+        return result;
+    }
+    
+    void appendRoman(int n, string& s, char symbol[]) {
+        assert(n <= 9);
+        
+        if (n == 0) return;
+        if (n <= 3) {
+            s.append(n, symbol[0]);
+        }
+        else if (n == 4) {
+            s.append(1, symbol[0]);
+            s.append(1, symbol[1]);
+        }
+        else if (n <= 8) {
+            s.append(1, symbol[1]);
+            s.append(n - 5, symbol[0]);
+        }
+        else if (n == 9) {
+            s.append(1, symbol[0]);
+            s.append(1, symbol[2]);
+        }
+    }
+};