From 9408c9e573d61a59384c77eaa94f55152fec74e8 Mon Sep 17 00:00:00 2001
From: "Neil.Liu" <88214924@qq.com>
Date: Thu, 3 Jun 2021 14:30:31 +0800
Subject: [PATCH 1/2] =?UTF-8?q?=E6=B7=BB=E5=8A=A00028.=E5=AE=9E=E7=8E=B0st?=
=?UTF-8?q?rStr=20Go=E8=AF=AD=E8=A8=80=E7=89=88=E6=9C=AC?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
---
problems/0028.实现strStr.md | 90 ++++++++++++++++++++++++++++++++++-
1 file changed, 89 insertions(+), 1 deletion(-)
diff --git a/problems/0028.实现strStr.md b/problems/0028.实现strStr.md
index b8ebcaa1..1dba5a38 100644
--- a/problems/0028.实现strStr.md
+++ b/problems/0028.实现strStr.md
@@ -726,10 +726,98 @@ class Solution:
Go：
+```go
+// 方法一:前缀表使用减1实现
+
+// getNext 构造前缀表next
+// params:
+// next 前缀表数组
+// s 模式串
+func getNext(next []int, s string) {
+ j := -1 // j表示 最长相等前后缀长度
+ next[0] = j
+
+ for i := 1; i < len(s); i++ {
+ for j >= 0 && s[i] != s[j+1] {
+ j = next[j] // 回退前一位
+ }
+ if s[i] == s[j+1] {
+ j++
+ }
+ next[i] = j // next[i]是i（包括i）之前的最长相等前后缀长度
+ }
+}
+func strStr(haystack string, needle string) int {
+ if len(needle) == 0 {
+ return 0
+ }
+ next := make([]int, len(needle))
+ getNext(next, needle)
+ j := -1 // 模式串的起始位置 next为-1 因此也为-1
+ for i := 0; i < len(haystack); i++ {
+ for j >= 0 && haystack[i] != needle[j+1] {
+ j = next[j] // 寻找下一个匹配点
+ }
+ if haystack[i] == needle[j+1] {
+ j++
+ }
+ if j == len(needle)-1 { // j指向了模式串的末尾
+ return i - len(needle) + 1
+ }
+ }
+ return -1
+}
+```
+
+```go
+// 方法二: 前缀表无减一或者右移
+
+// getNext 构造前缀表next
+// params:
+// next 前缀表数组
+// s 模式串
+func getNext(next []int, s string) {
+ j := 0
+ next[0] = j
+ for i := 1; i < len(s); i++ {
+ for j > 0 && s[i] != s[j] {
+ j = next[j-1]
+ }
+ if s[i] == s[j] {
+ j++
+ }
+ next[i] = j
+ }
+}
+func strStr(haystack string, needle string) int {
+ n := len(needle)
+ if n == 0 {
+ return 0
+ }
+ j := 0
+ next := make([]int, n)
+ getNext(next, needle)
+ for i := 0; i < len(haystack); i++ {
+ for j > 0 && haystack[i] != needle[j] {
+ j = next[j-1] // 回退到j的前一位
+ }
+ if haystack[i] == needle[j] {
+ j++
+ }
+ if j == n {
+ return i - n + 1
+ }
+ }
+ return -1
+}
+```
+
+
+
-----------------------
* 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)
* B站视频：[代码随想录](https://space.bilibili.com/525438321)
* 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ)
-
+
\ No newline at end of file
From 7bf42a83f42131f87c881a42567994379ceb6b8c Mon Sep 17 00:00:00 2001
From: "Neil.Liu" <88214924@qq.com>
Date: Thu, 3 Jun 2021 15:42:44 +0800
Subject: [PATCH 2/2] =?UTF-8?q?=E6=B7=BB=E5=8A=A00459.=E9=87=8D=E5=A4=8D?=
=?UTF-8?q?=E7=9A=84=E5=AD=90=E5=AD=97=E7=AC=A6=E4=B8=B2=20Go=E8=AF=AD?=
=?UTF-8?q?=E8=A8=80=E7=89=88=E6=9C=AC?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
---
problems/0459.重复的子字符串.md | 60 +++++++++++++++++++++++++-
1 file changed, 59 insertions(+), 1 deletion(-)
diff --git a/problems/0459.重复的子字符串.md b/problems/0459.重复的子字符串.md
index 51a903ef..deb755bf 100644
--- a/problems/0459.重复的子字符串.md
+++ b/problems/0459.重复的子字符串.md
@@ -236,6 +236,64 @@ class Solution:
Go：
+这里使用了前缀表统一减一的实现方式
+
+```go
+func repeatedSubstringPattern(s string) bool {
+ n := len(s)
+ if n == 0 {
+ return false
+ }
+ next := make([]int, n)
+ j := -1
+ next[0] = j
+ for i := 1; i < n; i++ {
+ for j >= 0 && s[i] != s[j+1] {
+ j = next[j]
+ }
+ if s[i] == s[j+1] {
+ j++
+ }
+ next[i] = j
+ }
+ // next[n-1]+1 最长相同前后缀的长度
+ if next[n-1] != -1 && n%(n-(next[n-1]+1)) == 0 {
+ return true
+ }
+ return false
+}
+```
+
+前缀表（不减一）的代码实现
+
+```go
+func repeatedSubstringPattern(s string) bool {
+ n := len(s)
+ if n == 0 {
+ return false
+ }
+ j := 0
+ next := make([]int, n)
+ next[0] = j
+ for i := 1; i < n; i++ {
+ for j > 0 && s[i] != s[j] {
+ j = next[j-1]
+ }
+ if s[i] == s[j] {
+ j++
+ }
+ next[i] = j
+ }
+ // next[n-1] 最长相同前后缀的长度
+ if next[n-1] != 0 && n%(n-next[n-1]) == 0 {
+ return true
+ }
+ return false
+}
+```
+
+
+
@@ -243,4 +301,4 @@ Go：
* 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)
* B站视频：[代码随想录](https://space.bilibili.com/525438321)
* 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ)
-
+
\ No newline at end of file
