2023-02-04 update: added "13. Roman to Integer"

Author: fartem

README.md

@@ -16,3 +16,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 |----------------------|----------------------------------------------------------|-------------------------------------------|
 | 1. Two Sum           | [Link](https://leetcode.com/problems/two-sum/)           | [Link](./lib/easy/two_sum.dart)           |
 | 9. Palindrome Number | [Link](https://leetcode.com/problems/palindrome-number/) | [Link](./lib/easy/palindrome_number.dart) |
+| 13. Roman to Integer | [Link](https://leetcode.com/problems/roman-to-integer/)  | [Link](./lib/easy/roman_to_integer.dart)  |

lib/easy/roman_to_integer.dart

@@ -0,0 +1,24 @@
+// https://leetcode.com/problems/roman-to-integer/
+class Solution {
+  int romanToInt(String s) {
+    final values = <String, int>{
+      'I': 1,
+      'V': 5,
+      'X': 10,
+      'L': 50,
+      'C': 100,
+      'D': 500,
+      'M': 1000,
+    };
+    int result = 0;
+    for (int i = s.length - 1; i >= 0; i--) {
+      int curr = values[s[i]]!;
+      if (curr * 4 < result) {
+        result -= curr;
+      } else {
+        result += curr;
+      }
+    }
+    return result;
+  }
+}

test/easy/roman_to_integer_test.dart

@@ -0,0 +1,14 @@
+import 'package:leetcode_dart/easy/roman_to_integer.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group(
+    'Example tests',
+    () {
+      final rti = Solution();
+      test('3', () => expect(3, rti.romanToInt('III')));
+      test('58', () => expect(3, rti.romanToInt('LVIII')));
+      test('1994', () => expect(3, rti.romanToInt('MCMXCIV')));
+    },
+  );
+}