Update shortest-matching-substring.py

Author: kamyu104

Python/shortest-matching-substring.py

@@ -3,6 +3,64 @@
 
 # kmp, two pointers (three pointers)
 class Solution(object):
+    def shortestMatchingSubstring(self, s, p):
+        """
+        :type s: str
+        :type p: str
+        :rtype: int
+        """
+        INF = float("inf")
+        def getPrefix(pattern):
+            prefix = [-1]*len(pattern)
+            j = -1
+            for i in xrange(1, len(pattern)):
+                while j+1 > 0 and pattern[j+1] != pattern[i]:
+                    j = prefix[j]
+                if pattern[j+1] == pattern[i]:
+                    j += 1
+                prefix[i] = j
+            return prefix
+
+        def KMP(text, pattern):
+            if not pattern:
+                for i in xrange(len(text)+1):
+                    yield i
+                return
+            prefix = getPrefix(pattern)
+            j = -1
+            for i in xrange(len(text)):
+                while j+1 > 0 and pattern[j+1] != text[i]:
+                    j = prefix[j]
+                if pattern[j+1] == text[i]:
+                    j += 1
+                if j+1 == len(pattern):
+                    yield i-j
+                    j = prefix[j]
+        
+        a, b, c = p.split('*')
+        n = len(s)
+        la, lb, lc = len(a), len(b), len(c)
+        result = INF
+        j = k = 0
+        jt = KMP(s, b)
+        kt = KMP(s, c)
+        for i in KMP(s, a):
+            while j != -1 and j < i+la:
+                j = next(jt, -1)
+            if j == -1:
+                break
+            while k != -1 and k < j+lb:
+                k = next(kt, -1)
+            if k == -1:
+                break
+            result = min(result, (k+lc)-i)
+        return result if result != INF else -1 
+            
+
+# Time:  O(n + m)
+# Space: O(n + m)
+# kmp, two pointers (three pointers)
+class Solution2(object):
     def shortestMatchingSubstring(self, s, p):
         """
         :type s: str