387 finish. 16ms

Author: aQua

Algorithms/0387.first-unique-character-in-a-string/README.md

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+# [387. First Unique Character in a String](https://leetcode.com/problems/first-unique-character-in-a-string/)
+
+## 题目
+
+Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1.
+
+Examples:
+
+```text
+s = "leetcode"
+return 0.
+
+s = "loveleetcode",
+return 2.
+```
+
+Note: You may assume the string contain only lowercase letters.
+
+## 解题思路
+
+见程序注释

Algorithms/0387.first-unique-character-in-a-string/first-unique-character-in-a-string.go

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+package Problem0387
+
+func firstUniqChar(s string) int {
+	rec := make([]int, 26)
+	for _, b := range s {
+		rec[b-'a']++
+	}
+
+	for i, b := range s {
+		if rec[b-'a'] == 1 {
+			return i
+		}
+	}
+
+	return -1
+}

Algorithms/0387.first-unique-character-in-a-string/first-unique-character-in-a-string_test.go

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+package Problem0387
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// tcs is testcase slice
+var tcs = []struct {
+	s   string
+	ans int
+}{
+
+	{
+		"leetcode",
+		0,
+	},
+
+	{
+		"loveleetcode",
+		2,
+	},
+
+	{"aabbcc", -1},
+
+	// 可以有多个 testcase
+}
+
+func Test_firstUniqChar(t *testing.T) {
+	ast := assert.New(t)
+
+	for _, tc := range tcs {
+		fmt.Printf("~~%v~~\n", tc)
+		ast.Equal(tc.ans, firstUniqChar(tc.s), "输入:%v", tc)
+	}
+}
+
+func Benchmark_firstUniqChar(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tc := range tcs {
+			firstUniqChar(tc.s)
+		}
+	}
+}