hellcoderz
diff --git a/‎builtins/dictionary.py b/‎builtins/dictionary.py
diff --git a/‎builtins/list.py b/‎builtins/list.py
diff --git a/‎builtins/set.py b/‎builtins/set.py
diff --git a/‎builtins/tuple.py
Lines changed: 0 additions & 14 deletions b/‎builtins/tuple.py
Lines changed: 0 additions & 14 deletions
diff --git a/‎queue/zigzagiterator.py
Lines changed: 31 additions & 0 deletions b/‎queue/zigzagiterator.py
Lines changed: 31 additions & 0 deletions
diff --git a/‎string/word_squares.py
Lines changed: 21 additions & 0 deletions b/‎string/word_squares.py
Lines changed: 21 additions & 0 deletions
@@ -0,0 +1,31 @@
+class ZigZagIterator:
+    def __init__(self, v1, v2):
+        """
+        Initialize your data structure here.
+        :type v1: List[int]
+        :type v2: List[int]
+        """
+        self.queue=[_ for _ in (v1,v2) if _]
+        print(self.queue)
+
+    def next(self):
+        """
+        :rtype: int
+        """
+        v=self.queue.pop(0)
+        ret=v.pop(0)
+        if v: self.queue.append(v)
+        return ret
+
+    def has_next(self):
+        """
+        :rtype: bool
+        """
+        if self.queue: return True
+        return False
+
+l1 = [1, 2]
+l2 = [3, 4, 5, 6]
+it = ZigZagIterator(l1, l2)
+while it.has_next():
+    print(it.next())
@@ -0,0 +1,21 @@
+import collections
+
+def word_squares(words):
+    n = len(words[0])
+    fulls = collections.defaultdict(list)
+    for word in words:
+        for i in range(n):
+            fulls[word[:i]].append(word)
+    def build(square):
+        if len(square) == n:
+            squares.append(square)
+            return
+        for word in fulls[''.join(zip(*square)[len(square)])]:
+            build(square + [word])
+    squares = []
+    for word in words:
+        build([word])
+    return squares
+
+dic = ["at","baba","atan","atal"]
+print(word_squares(dic))