add permutation in string solution

Author: lazybing

python/leetcode567_permutation_in_string/solution.py

@@ -0,0 +1,87 @@
+class Solution:
+    #generate the sub string
+    def perm(self, s:str)->str:
+        if len(s) <= 1:
+            return [s]
+
+        s1 = []
+        for i in range(len(s)):
+            for j in self.perm(s[0:i] + s[i + 1:]):
+                s1.append(s[i] + j)
+
+        return s1
+
+    def checkInclusion(self, s1:str, s2:str)->bool:
+        if (len(s1) > len(s2)):
+            return False
+
+        s1_perm = list(set(self.perm(s1)))
+        #check if the perm str of s1 is the substr of s2
+        for i in s1_perm:
+            idx = s2.find(i)
+            if idx != -1:
+                return True
+
+        return False
+
+class Solution:
+    def match(self, s1:str, s2:str)->bool:
+        for i in range(26):
+            if s1[i] != s2[i]:
+                return False
+        return True
+
+    def checkInclusion(self, s1:str, s2:str)->bool:
+        if (len(s1) > len(s2)):
+            return False
+
+        list1 = [0 for i in range(26)]
+        list2 = [0 for i in range(26)]
+        
+        for i in range(len(s1)):
+            list1[ord(s1[i]) - ord['a']] += 1
+            list2[ord(s2[i]) - ord['a']] += 1
+
+        for i in range(len(s2) - len(s1)):
+            if self.match(list1, list2):
+                return True
+            list2[ord(s2[i + len(s1)]) - ord('a')] += 1
+            list2[ord(s2[i]) - ord('a')] -= 1
+
+        return self.match(list1, list2)
+
+class Solution:
+    def checkInclusion(self, s1:str, s2:str)->bool:
+        if (len(s1)) > len(s2):
+            return False
+        list1 = [0 for in range(26)]
+        list2 = [0 for in range(26)]
+
+        for i in range(len(s1)):
+            list1[ord(s1[i]) - ord('a')] += 1
+            list2[ord(s2[i]) - ord('a')] += 1
+
+        count = 0
+        for i in range(26):
+            if list1[i] == list2[i]:
+                count += 1
+
+        for i in range(len(s2) - len(s1)):
+            r = ord(s2[i + len(s1)]) - ord('a')
+            l = ord(s2[i]) - ord('a')
+            if count == 26:
+                return True
+
+            list2[r] += 1
+            if list2[r] == list1[r]:
+                count += 1
+            elif list2[r] == list1[r] + 1:
+                count -= 1
+
+            list2[l] -= 1
+            if list2[l] == list1[1]:
+                count += 1
+            elif list2[l] == list1[l] - 1:
+                count -= 1
+
+        return count == 26