feat: commit solution

Author: lxlxw

_sidebar.md

@@ -16,12 +16,12 @@
   - [21.合并两个有序链表 ✅](solution/1-99/0021.merge-two-sorted-lists/)
   - [26.删除排序数组中的重复项 ✅](solution/1-99/0026.remove-duplicates-from-sorted-array/)
   - [27.移除元素 ✅](solution/1-99/0027.remove-element/)
+  - [28.实现 strStr() ✅](solution/1-99/0028.implement-strstr/)
   - [88.合并两个有序数组](solution/1-99/0088.merge-sorted-array/)
   - [125.验证回文串 ✅](solution/100-199/0125.valid-palindrome/)
 
 
 
 
-
 
 

index-tags.md

@@ -17,6 +17,7 @@
 |  [13](https://leetcode-cn.com/problems/roman-to-integer)  |  [罗马数字转整数](/solution/1-99/0013.roman-to-integer/)  |  `数学`,`字符串`  |  <font color=green>简单</font>  |✅ |
 |  [20](https://leetcode-cn.com/problems/valid-parentheses)  |  [有效的括号](/solution/1-99/0020.valid-parentheses/)  |  `栈`,`字符串`  |  <font color=green>简单</font>  |✅ |
 |  [125](https://leetcode-cn.com/problems/valid-palindrome)  |  [验证回文串](/solution/100-199/0125.valid-palindrome/)  |  `双指针`,`字符串`  |  <font color=green>简单</font>  |✅ |
+|  [28](https://leetcode-cn.com/problems/implement-strstr)  |  [实现 strstr()](/solution/1-99/0028.implement-strstr%28%29/)  |  `双指针`,`字符串`  |  <font color=green>简单</font>  |✅ |
 
 #### **数组**
 
@@ -41,6 +42,16 @@
 
 #### **堆**
 
+#### **双指针**
+
+|  题号  |  题解  |  标签  | 难度  | 是否解题 |
+| --- | --- | --- | --- | --- |
+|  [26](https://leetcode-cn.com/problems/remove-duplicates-from-sorted-array)  |  [删除排序数组中的重复项](/solution/1-99/0026.remove-duplicates-from-sorted-array/)  |  `数组`,`双指针`  |  <font color=green>简单</font>  |✅ |
+|  [27](https://leetcode-cn.com/problems/remove-element)  |  [移除元素](/solution/1-99/0027.remove-element/)  |  `数组`,`双指针`  |  <font color=green>简单</font>  |✅ |
+|  [88](https://leetcode-cn.com/problems/merge-sorted-array)  |  [合并两个有序数组](/solution/1-99/0088.merge-sorted-array/)  |  `数组`,`双指针`  |  <font color=green>简单</font>  |✅ |
+|  [125](https://leetcode-cn.com/problems/valid-palindrome)  |  [验证回文串](/solution/100-199/0125.valid-palindrome/)  |  `双指针`,`字符串`  |  <font color=green>简单</font>  |✅ |
+|  [28](https://leetcode-cn.com/problems/implement-strstr)  |  [实现 strstr()](/solution/1-99/0028.implement-strstr%28%29/)  |  `双指针`,`字符串`  |  <font color=green>简单</font>  |✅ |
+
 #### **链表**
 
 |  题号  |  题解  |  标签  | 难度  | 是否解题 |
@@ -57,15 +68,6 @@
 
 #### **二分查找**
 
-#### **双指针**
-
-|  题号  |  题解  |  标签  | 难度  | 是否解题 |
-| --- | --- | --- | --- | --- |
-|  [26](https://leetcode-cn.com/problems/remove-duplicates-from-sorted-array)  |  [删除排序数组中的重复项](/solution/1-99/0026.remove-duplicates-from-sorted-array/)  |  `数组`,`双指针`  |  <font color=green>简单</font>  |✅ |
-|  [27](https://leetcode-cn.com/problems/remove-element)  |  [移除元素](/solution/1-99/0027.remove-element/)  |  `数组`,`双指针`  |  <font color=green>简单</font>  |✅ |
-|  [88](https://leetcode-cn.com/problems/merge-sorted-array)  |  [合并两个有序数组](/solution/1-99/0088.merge-sorted-array/)  |  `数组`,`双指针`  |  <font color=green>简单</font>  |✅ |
-|  [125](https://leetcode-cn.com/problems/valid-palindrome)  |  [验证回文串](/solution/100-199/0125.valid-palindrome/)  |  `双指针`,`字符串`  |  <font color=green>简单</font>  |✅ |
-
 #### **递归**
 
 #### **深度优先搜素**

index-type.md

@@ -16,7 +16,7 @@
 |  [21](https://leetcode-cn.com/problems/merge-two-sorted-lists)  |  [合并两个有序链表](/solution/1-99/0021.merge-two-sorted-lists/)  |  `链表`  |  <font color=green>简单</font>  |✅ |
 |  [26](https://leetcode-cn.com/problems/remove-duplicates-from-sorted-array)  |  [删除排序数组中的重复项](/solution/1-99/0026.remove-duplicates-from-sorted-array/)  |  `数组`,`双指针`  |  <font color=green>简单</font>  |✅ |
 |  [27](https://leetcode-cn.com/problems/remove-element)  |  [移除元素](/solution/1-99/0027.remove-element/)  |  `数组`,`双指针`  |  <font color=green>简单</font>  |✅ |
-|  [28](https://leetcode-cn.com/problems/implement-strstr)  |  [实现 strstr()](/solution/1-99/0028.implement-strstr%28%29/)  |  `双指针`,`字符串`  |  <font color=green>简单</font>  |
+|  [28](https://leetcode-cn.com/problems/implement-strstr)  |  [实现 strstr()](/solution/1-99/0028.implement-strstr%28%29/)  |  `双指针`,`字符串`  |  <font color=green>简单</font>  |✅ |
 |  [35](https://leetcode-cn.com/problems/search-insert-position)  |  [搜索插入位置](/solution/1-99/0035.search-insert-position/)  |  `数组`,`二分查找`  |  <font color=green>简单</font>  |
 |  [38](https://leetcode-cn.com/problems/count-and-say)  |  [外观数列](/solution/1-99/0038.count-and-say/)  |  `字符串`  |  <font color=green>简单</font>  |
 |  [53](https://leetcode-cn.com/problems/maximum-subarray)  |  [最大子序和](/solution/1-99/0053.maximum-subarray/)  |  `数组`,`分治算法`,`动态规划`  |  <font color=green>简单</font>  |

solution/1-99/0028.implement-strstr/README.md

@@ -0,0 +1,67 @@
+# [28.实现 strStr()](https://leetcode-cn.com/problems/implement-strstr)
+
+
+### 题目描述
+
+<div class="notranslate"><p>实现&nbsp;<a href="https://baike.baidu.com/item/strstr/811469">strStr()</a>&nbsp;函数。</p>
+
+<p>给定一个&nbsp;haystack 字符串和一个 needle 字符串，在 haystack 字符串中找出 needle 字符串出现的第一个位置 (从0开始)。如果不存在，则返回&nbsp; <strong>-1</strong>。</p>
+
+<p><strong>示例 1:</strong></p>
+
+<pre><strong>输入:</strong> haystack = "hello", needle = "ll"
+<strong>输出:</strong> 2
+</pre>
+
+<p><strong>示例 2:</strong></p>
+
+<pre><strong>输入:</strong> haystack = "aaaaa", needle = "bba"
+<strong>输出:</strong> -1
+</pre>
+
+<p><strong>说明:</strong></p>
+
+<p>当&nbsp;<code>needle</code>&nbsp;是空字符串时，我们应当返回什么值呢？这是一个在面试中很好的问题。</p>
+
+<p>对于本题而言，当&nbsp;<code>needle</code>&nbsp;是空字符串时我们应当返回 0 。这与C语言的&nbsp;<a href="https://baike.baidu.com/item/strstr/811469">strstr()</a>&nbsp;以及 Java的&nbsp;<a href="https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#indexOf(java.lang.String)">indexOf()</a>&nbsp;定义相符。</p>
+</div>
+
+
+### 解题思路
+
+![](http://lc-photo.xwlin.com/28-1.png)
+![](http://lc-photo.xwlin.com/28-2.png)
+![](http://lc-photo.xwlin.com/28-3.png)
+![](http://lc-photo.xwlin.com/28-4.png)
+
+
+### 代码实现
+
+<!-- tabs:start -->
+
+#### **Golang**
+```go
+func strStr(haystack string, needle string) int {
+	if needle == "" {
+		return 0
+	}
+	p := 0
+	q := 0
+	for q < len(needle) && p < len(haystack) {
+		if haystack[p:p+1] == needle[q:q+1] {
+			q++
+		} else {
+			p = p - q
+			q = 0
+		}
+		p++
+	}
+	if q != len(needle) {
+		return -1
+	}
+	return p - q
+}
+```
+
+
+<!-- tabs:end -->

solution/1-99/0028.implement-strstr/solution.go

@@ -0,0 +1,31 @@
+package leetcode
+
+/*
+ * @lc app=leetcode.cn id=28 lang=golang
+ *
+ * [28] 实现 strStr()
+ */
+
+// @lc code=start
+func strStr(haystack string, needle string) int {
+	if needle == "" {
+		return 0
+	}
+	p := 0
+	q := 0
+	for q < len(needle) && p < len(haystack) {
+		if haystack[p:p+1] == needle[q:q+1] {
+			q++
+		} else {
+			p = p - q
+			q = 0
+		}
+		p++
+	}
+	if q != len(needle) {
+		return -1
+	}
+	return p - q
+}
+
+// @lc code=end

solution/1-99/0028.implement-strstr/solution_test.go

@@ -0,0 +1,46 @@
+package leetcode
+
+import (
+	"testing"
+)
+
+func TestStrStr(t *testing.T) {
+	var haystack string
+	var needle string
+	var ret int
+
+	haystack = "aaa"
+	needle = ""
+	ret = 0
+	if ret != strStr(haystack, needle) {
+		t.Fatalf("case fails: %v\n", ret)
+	}
+
+	haystack = "aaa"
+	needle = "a"
+	ret = 0
+	if ret != strStr(haystack, needle) {
+		t.Fatalf("case fails: %v\n", ret)
+	}
+
+	haystack = "hello"
+	needle = "ll"
+	ret = 2
+	if ret != strStr(haystack, needle) {
+		t.Fatalf("case fails: %v\n", ret)
+	}
+
+	haystack = "aaaaa"
+	needle = "bba"
+	ret = -1
+	if ret != strStr(haystack, needle) {
+		t.Fatalf("case fails: %v\n", ret)
+	}
+
+	haystack = "mississippi"
+	needle = "issipi"
+	ret = -1
+	if ret != strStr(haystack, needle) {
+		t.Fatalf("case fails: %v\n", ret)
+	}
+}