Create stamping-the-sequence.py

Author: kamyu104

Python/stamping-the-sequence.py

@@ -0,0 +1,47 @@
+# Time:  O((n - m) * m)
+# Space: O((n - m) * m)
+
+import collections
+
+
+class Solution(object):
+    def movesToStamp(self, stamp, target):
+        M, N = len(stamp), len(target)
+
+        q = collections.deque()
+        lookup = [False]*N
+        result = []
+        A = []
+        for i in xrange(N-M+1):
+            made, todo = set(), set()
+            for j, c in enumerate(stamp):
+                if c == target[i+j]:
+                    made.add(i+j)
+                else:
+                    todo.add(i+j)
+            A.append((made, todo))
+            if todo:
+                continue
+            result.append(i)
+            for m in made:
+                if lookup[m]:
+                    continue
+                q.append(m)
+                lookup[m] = True
+
+        while q:
+            i = q.popleft()
+            for j in xrange(max(0, i-M+1), min(N-M, i)+1):
+                made, todo = A[j]
+                if i not in todo:
+                    continue
+                todo.discard(i)
+                if todo:
+                    continue
+                result.append(j)
+                for m in made:
+                    if lookup[m]:
+                        continue
+                    q.append(m)
+                    lookup[m] = True
+        return result[::-1] if all(lookup) else []