LeetCode: 13 solved

Author: devMEremenko

Python/LeetCode/13. Roman to Integer.py

@@ -3,6 +3,44 @@
 class Solution:
 
     def romanToInt(self, s: str) -> int:
+        # return self.solution1(s)
+        # return self.solution2(s)
+        return self.solution3(s)
+
+    def solution1(self, s):
+        m = {'I': 1, 'V': 5, 'X': 10, 'L': 50, 'C': 100, 'D': 500, 'M': 1000}
+            
+        buf = 0
+        res = 0
+                
+        for i in range(len(s)):
+            current = m[s[i]]
+            isLast = i+1 == len(s)
+            
+            if isLast or current >= m[s[i+1]]:
+                res += current - buf
+                buf = 0
+            else:
+                buf += current
+                
+        return res
+    
+    def solution2(self, s):
+        m = {'I': 1, 'V': 5, 'X': 10, 'L': 50, 'C': 100, 'D': 500, 'M': 1000}
+        
+        prev = 0
+        res = 0
+        
+        for c in s:
+            if m[c] <= prev:
+                res += prev
+            else:
+                res -= prev
+            prev = m[c]
+                
+        return res + prev
+
+    def solution3(self, s):
         if not s: 
             return 0
 
@@ -17,4 +55,3 @@ def romanToInt(self, s: str) -> int:
                 res += roman[s[idx]]
 
         return res
-