parenthesizations_as_ints.py

dotfiles/lib/python/parenthesizations_as_ints.py

@@ -0,0 +1,31 @@
+from backports.functools_lru_cache import lru_cache
+
+
+def parenthesizations2h(pair_count):
+    return [
+        '{0:b}'.format(item).replace('1', '(').replace('0', ')')
+        for item in parenthesizations.parenthesizations(pair_count)
+    ]
+
+def parenthesizations2(pair_count):
+    """Parenthesizations returned encoded as numbers
+    """
+    parenthesizations = _parenthesizations2(pair_count * 2, net=0)
+    return parenthesizations
+
+
+@lru_cache(maxsize=None)
+def _parenthesizations2(length, net=0):
+    if net > length or net < 0:
+        raise Exception()
+    if net == length:
+        return [0]
+    res = add_bit(length-1, _parenthesizations(length-1, net=net + 1))
+    if net > 0:
+        res.extend(_parenthesizations(length-1, net=net - 1))
+    return res
+
+
+def add_bit(bitindex, items):
+    value = 2 ** bitindex
+    return [value + item for item in items]