feat: 0028. Find the Index of the First Occurrence in a String

kimi0230 · May 6, 2024 · 2e4175d · 2e4175d
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diff --git a/Leetcode/0028.Find-the-Index-of-the-First-Occurrence-in-a-String/README.md b/Leetcode/0028.Find-the-Index-of-the-First-Occurrence-in-a-String/README.md
@@ -80,6 +80,47 @@ seo:
 https://github.com/kimi0230/LeetcodeGolang/blob/master/Leetcode/0028.Find-the-Index-of-the-First-Occurrence-in-a-String/main.go
 
 ```go
+package findtheindexofthefirstoccurrenceinastring
+
+// 暴力解
+// 時間複雜 O(M*N), 空間複雜 O()
+func strStr(haystack string, needle string) int {
+	haystackLen := len(haystack)
+	needleLen := len(needle)
+	index := 0
+	for i := 0; i <= (haystackLen - needleLen); i++ {
+		j := 0
+		for j = 0; j < needleLen; j++ {
+			if haystack[i+j] == needle[j] {
+				index = i
+			} else {
+				break
+			}
+		}
+		if j == needleLen {
+			return index
+		}
+	}
+	return -1
+}
+
+// Slice 解法
+func strStrSlice(haystack string, needle string) int {
+	haystackLen := len(haystack)
+	needleLen := len(needle)
+	if haystackLen == 0 || haystackLen < needleLen {
+		return -1
+	}
+	if needleLen == 0 {
+		return 0
+	}
+	for i := 0; i <= (haystackLen - needleLen); i++ {
+		if haystack[i:i+needleLen] == needle {
+			return i
+		}
+	}
+	return -1
+}
 
 ```
 

diff --git a/Leetcode_labuladong/28.找出字符串中第一个匹配项的下标.go b/Leetcode_labuladong/28.找出字符串中第一个匹配项的下标.go
@@ -0,0 +1,71 @@
+// 時間複雜度:
+// 空間複雜度:
+/*
+ * @lc app=leetcode.cn id=28 lang=golang
+ *
+ * [28] 找出字符串中第一个匹配项的下标
+ *
+ * https://leetcode.cn/problems/find-the-index-of-the-first-occurrence-in-a-string/description/
+ *
+ * algorithms
+ * Easy (43.50%)
+ * Likes:    2214
+ * Dislikes: 0
+ * Total Accepted:    1.1M
+ * Total Submissions: 2.4M
+ * Testcase Example:  '"sadbutsad"\n"sad"'
+ *
+ * 给你两个字符串 haystack 和 needle ，请你在 haystack 字符串中找出 needle 字符串的第一个匹配项的下标（下标从 0
+ * 开始）。如果 needle 不是 haystack 的一部分，则返回  -1 。
+ *
+ *
+ *
+ * 示例 1：
+ *
+ *
+ * 输入：haystack = "sadbutsad", needle = "sad"
+ * 输出：0
+ * 解释："sad" 在下标 0 和 6 处匹配。
+ * 第一个匹配项的下标是 0 ，所以返回 0 。
+ *
+ *
+ * 示例 2：
+ *
+ *
+ * 输入：haystack = "leetcode", needle = "leeto"
+ * 输出：-1
+ * 解释："leeto" 没有在 "leetcode" 中出现，所以返回 -1 。
+ *
+ *
+ *
+ *
+ * 提示：
+ *
+ *
+ * 1 <= haystack.length, needle.length <= 10^4
+ * haystack 和 needle 仅由小写英文字符组成
+ *
+ *
+ */
+
+// @lc code=start
+func strStr(haystack string, needle string) int {
+	hLen := len(haystack)
+	nLen := len(needle)
+	if hLen < 0 || hLen < nLen {
+		return -1
+	}
+	if nLen == 0 {
+		return 0
+	}
+
+	for i := 0; i <= (hLen - nLen); i++ {
+		if haystack[i:i+nLen] == needle {
+			return i
+		}
+	}
+	return -1
+}
+
+// @lc code=end
+