roman to insteger

Author: itcuihao

problems/0013.roman-to-integer/README.md

@@ -42,3 +42,5 @@ Example 5:
 Input: "MCMXCIV"
 Output: 1994
 Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
+
+- 倒序遍历，当遇到左边元素比右边小的时候就减掉

problems/0013.roman-to-integer/run.go

@@ -1,40 +1,31 @@
 package integer
 
-import "fmt"
-
 // 到着遍历？
 func romanToInt(s string) int {
 	k := 0
 	ls := len(s)
 	if ls == 0 {
 		return k
 	}
-	roman := map[string]int{
-		"I": 1,
-		"V": 5,
-		"X": 10,
-		"L": 50,
-		"C": 100,
-		"D": 500,
-		"M": 1000,
+	roman := map[byte]int{
+		'I': 1,
+		'V': 5,
+		'X': 10,
+		'L': 50,
+		'C': 100,
+		'D': 500,
+		'M': 1000,
 	}
-	getRoman := func(k string) int {
-		if v, ok := roman[k]; ok {
+	getRoman := func(b byte) int {
+		if v, ok := roman[b]; ok {
 			return v
 		}
 		return 0
 	}
 
-	if ls == 1 {
-		k = getRoman(s)
-		return k
-	}
-
 	tn := 0
 	for i := ls - 1; i >= 0; i-- {
-		tmp := getRoman(string(s[i]))
-
-		fmt.Println("/", tmp)
+		tmp := getRoman(s[i])
 
 		if tmp < tn {
 			k -= tmp