Add Solution in Python

WANGZijian1994 · WANGZijian1994 · commit 6e0c55ad732b · 2020-05-18T10:19:45.000+02:00
diff --git a/May-LeetCoding-Challenge/18-Permutation-In-String/Permutation-in-String.py b/May-LeetCoding-Challenge/18-Permutation-In-String/Permutation-in-String.py
@@ -0,0 +1,25 @@
+class Solution:
+    def checkInclusion(self, s1: str, s2: str) -> bool:
+        need = dict(collections.Counter(s1))
+        window = {}
+        left,right = 0,0
+        while right < len(s2):
+            letter = s2[right]
+            if letter not in need:
+                window.clear()
+                left = right+1
+            else:
+                window[letter]=window.get(letter,0)+1
+                if window==need:
+                    return True
+                if window[letter]>need[letter]:
+                    while left<=right:
+                        if s2[left]!=letter:
+                            window[s2[left]] = window.get(s2[left],0)-1
+                            left+=1
+                        else:
+                            left+=1
+                            break
+                    window[letter]-=1
+            right+=1
+        return False
