Merge pull request #86 from kingeasternsun/patch-1

Update 0387.First-Unique-Character-in-a-String.md

leetcode/0387.First-Unique-Character-in-a-String/387. First Unique Character in a String.go

@@ -1,5 +1,6 @@
 package leetcode
 
+// 解法一
 func firstUniqChar(s string) int {
 	result := make([]int, 26)
 	for i := 0; i < len(s); i++ {
@@ -12,3 +13,34 @@ func firstUniqChar(s string) int {
 	}
 	return -1
 }
+
+// 解法二
+// 执行用时: 8 ms
+// 内存消耗: 5.2 MB
+func firstUniqChar1(s string) int {
+	charMap := make([][2]int, 26)
+	for i := 0; i < 26; i++ {
+		charMap[i][0] = -1
+		charMap[i][1] = -1
+	}
+	for i := 0; i < len(s); i++ {
+		if charMap[s[i]-'a'][0] == -1 {
+			charMap[s[i]-'a'][0] = i
+		} else { //已经出现过
+			charMap[s[i]-'a'][1] = i
+		}
+	}
+	res := len(s)
+	for i := 0; i < 26; i++ {
+		//只出现了一次
+		if charMap[i][0] >= 0 && charMap[i][1] == -1 {
+			if charMap[i][0] < res {
+				res = charMap[i][0]
+			}
+		}
+	}
+	if res == len(s) {
+		return -1
+	}
+	return res
+}