finish Problem 28

Algorithms/0028.implement-strstr/README.md

@@ -1,10 +1,12 @@
 # [28. Implement strStr()](https://leetcode.com/problems/implement-strstr/)
 
 ## 题目
+Implement strStr().
 
+Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
 
 ## 解题思路
-
+依次对比查找
 
 ## 总结
 

Algorithms/0028.implement-strstr/implement-strstr.go

@@ -1,2 +1,13 @@
 package Problem0028
 
+func strStr(haystack string, needle string) int {
+	hlen, nlen := len(haystack), len(needle)
+	// 当hlen等于nlen的时候，需要i == 0
+	for i := 0; i <= hlen-nlen; i++ {
+		if haystack[i:i+nlen] == needle {
+			return i
+		}
+	}
+
+	return -1
+}

Algorithms/0028.implement-strstr/implement-strstr_test.go

@@ -1,8 +1,8 @@
 package Problem0028
 
 import (
-	"testing"
 	"fmt"
+	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -16,12 +16,13 @@ type question struct {
 // one 代表第一个参数
 type para struct {
 	one string
+	two string
 }
 
 // ans 是答案
 // one 代表第一个答案
 type ans struct {
-	one string
+	one int
 }
 
 func Test_Problem0028(t *testing.T) {
@@ -30,17 +31,32 @@ func Test_Problem0028(t *testing.T) {
 	qs := []question{
 
 		question{
-			para{""},
-			ans{""},
+			para{"", ""},
+			ans{0},
 		},
-
+
+		question{
+			para{"abcd", "bc"},
+			ans{1},
+		},
+
+		question{
+			para{"abcde", "c"},
+			ans{2},
+		},
+
+		question{
+			para{"abcde", "f"},
+			ans{-1},
+		},
+
 		// 如需多个测试，可以复制上方元素。
 	}
 
 	for _, q := range qs {
 		a, p := q.ans, q.para
 		fmt.Printf("~~%v~~\n", p)
 
-		ast.Equal(a.one, (p.one), "输入:%v", p)
+		ast.Equal(a.one, strStr(p.one, p.two), "输入:%v", p)
 	}
 }