Merge pull request #1891 from DraymondHIT/master

添加 0028找出字符串中第一个匹配项的下标 前缀表（不减一） Python 版本

problems/0028.实现strStr.md

@@ -769,6 +769,36 @@ class Solution:
         return next
 ```
 
+```python
+// 前缀表（不减一）Python实现
+class Solution:
+    def strStr(self, haystack: str, needle: str) -> int:
+        if len(needle) == 0:
+            return 0
+        next = self.getNext(needle)
+        j = 0
+        for i in range(len(haystack)):
+            while j >= 1 and haystack[i] != needle[j]:
+                j = next[j-1]
+            if haystack[i] == needle[j]:
+                j += 1
+            if j == len(needle):
+                return i - len(needle) + 1
+        return -1
+    
+    def getNext(self, needle):
+        next = [0] * len(needle)
+        j = 0
+        next[0] = j
+        for i in range(1, len(needle)):
+            while j >= 1 and needle[i] != needle[j]:
+                j = next[j-1]
+            if needle[i] == needle[j]:
+                j += 1
+            next[i] = j
+        return next
+```
+
 Go：
 
 ```go
@@ -1352,3 +1382,4 @@ impl Solution {
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>
 </a>
+