init commit

archive/algorithm/leetcode/13.go

@@ -0,0 +1,30 @@
+package main
+
+var mapping = map[string]int{
+	"I": 1,
+	"V": 5,
+	"X": 10,
+	"L": 50,
+	"C": 100,
+	"D": 500,
+	"M": 1000,
+}
+
+func romanToInt(s string) int {
+	var ret, last int
+	for _, chr := range s {
+		val := mapping[string(chr)]
+		if last < val {
+			ret = val + ret - (last * 2)
+		} else {
+			ret += val
+		}
+		last = val
+	}
+	return ret
+}
+
+func main() {
+	println(romanToInt("MCMXCIV")) //5
+	println(romanToInt("IIIV"))    //4
+}