roman_to_integer

Author: hitzzc

README.md

@@ -13,5 +13,6 @@ leetcode for golang
 #### [9. palindrome number](https://github.com/hitzzc/go-leetcode/tree/master/palindrome_number)
 #### [11. container with most water](https://github.com/hitzzc/go-leetcode/tree/master/container_with_most_water)
 #### [12. integer to roman](https://github.com/hitzzc/go-leetcode/tree/master/integer_to_roman)
+#### [12. roman to integer](https://github.com/hitzzc/go-leetcode/tree/master/roman_to_integer)
 
 

roman_to_integer/roman_to_integer.go

@@ -0,0 +1,26 @@
+package roman_to_integer
+
+func romanToInt(s string) int {
+	m := map[rune]int{
+		rune('I'): 1,
+		rune('V'): 5,
+		rune('X'): 10,
+		rune('L'): 50,
+		rune('C'): 100,
+		rune('D'): 500,
+		rune('M'): 1000,
+	}
+	runes := []rune(s)
+	if len(runes) == 1 {
+		return m[runes[0]]
+	}
+	ret := m[runes[0]]
+	for i := 1; i < len(runes); i++ {
+		if m[runes[i-1]] < m[runes[i]] {
+			ret += m[runes[i]] - 2*m[runes[i-1]]
+		} else {
+			ret += m[runes[i]]
+		}
+	}
+	return ret
+}

roman_to_integer/roman_to_integer_test.go

@@ -0,0 +1,9 @@
+package roman_to_integer
+
+import (
+	"testing"
+)
+
+func TestRomanToInt(t *testing.T) {
+
+}