diff --git a/AUTHORS b/AUTHORS
index edf1650a9..3faf3f77e 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -2,4 +2,5 @@ Gagandeep Singh<singh.23@iitj.ac.in>
Kartikei Mittal<kartikeimittal@gmail.com>
Umesh<23umesh.here@gmail.com>
Rohan Singh<singh.77@iitj.ac.in>
-Tarun Singh Tomar <tomartarun2001@gmail.com>
+Tarun Singh Tomar<tomartarun2001@gmail.com>
+Saptashrungi Birajdar<saptashrungib@gmail.com>
\ No newline at end of file
diff --git a/pydatastructs/miscellaneous_data_structures/stack.py b/pydatastructs/miscellaneous_data_structures/stack.py
index 6c4f8c5d4..6899eb774 100644
--- a/pydatastructs/miscellaneous_data_structures/stack.py
+++ b/pydatastructs/miscellaneous_data_structures/stack.py
@@ -1,4 +1,4 @@
-from pydatastructs.linear_data_structures import OneDimensionalArray
+from pydatastructs.linear_data_structures import DynamicOneDimensionalArray
from copy import deepcopy as dc
__all__ = [
@@ -19,13 +19,7 @@ class Stack(object):
By default, 'array'
Currently only supports 'array'
implementation.
- maxsize : int
- The maximum size of the stack.
- For array implementation.
- top : int
- The top element of the stack.
- For array implementation.
- items : OneDimensionalArray
+ items : DynamicOneDimensionalArray
Optional, by default, None
The inital items in the stack.
For array implementation.
@@ -39,12 +33,12 @@ class Stack(object):
=======
>>> from pydatastructs import Stack
- >>> s = Stack(maxsize=5, top=0)
+ >>> s = Stack()
>>> s.push(1)
>>> s.push(2)
>>> s.push(3)
>>> str(s)
- '[1, 2, 3, None, None]'
+ '[1, 2, 3]'
>>> s.pop()
3
@@ -57,8 +51,6 @@ class Stack(object):
def __new__(cls, implementation='array', **kwargs):
if implementation == 'array':
return ArrayStack(
- kwargs.get('maxsize', None),
- kwargs.get('top', 0),
kwargs.get('items', None),
kwargs.get('dtype', int))
raise NotImplementedError(
@@ -82,46 +74,36 @@ def peek(self):
class ArrayStack(Stack):
- __slots__ = ['maxsize', 'top', 'items', 'dtype']
+ __slots__ = ['items', 'dtype']
- def __new__(cls, maxsize=None, top=0, items=None, dtype=int):
- if not _check_type(maxsize, int):
- raise ValueError("maxsize is missing.")
- if not _check_type(top, int):
- raise TypeError("top is not of type int.")
+ def __new__(cls, items=None, dtype=int):
if items is None:
- items = OneDimensionalArray(dtype, maxsize)
- if not _check_type(items, OneDimensionalArray):
- raise ValueError("items is not of type, OneDimensionalArray")
- if items._size > maxsize:
- raise ValueError("Overflow, size of items %s is greater "
- "than maxsize, %s"%(items._size, maxsize))
+ items = DynamicOneDimensionalArray(dtype, 0)
+ else:
+ items = DynamicOneDimensionalArray(dtype, items)
obj = object.__new__(cls)
- obj.maxsize, obj.top, obj.items, obj.dtype = \
- maxsize, top, items, items._dtype
+ obj.items, obj.dtype = \
+ items, items._dtype
return obj
def push(self, x):
- if self.top == self.maxsize:
- raise ValueError("Stack is full.")
- self.items[self.top] = self.dtype(x)
- self.top += 1
+ self.items.append(x)
def pop(self):
- if self.top == 0:
- raise ValueError("Stack is already empty.")
- self.top -= 1
- r = self.items[self.top]
- self.items[self.top] = None
- return r
+ if self.is_empty:
+ raise ValueError("Stack is empty")
+
+ top_element = dc(self.items[self.items._last_pos_filled])
+ self.items.delete(self.items._last_pos_filled)
+ return top_element
@property
def is_empty(self):
- return self.top == 0
+ return self.items._last_pos_filled == -1
@property
def peek(self):
- return self.items[self.top - 1]
+ return self.items[self.items._last_pos_filled]
def __str__(self):
"""
diff --git a/pydatastructs/miscellaneous_data_structures/tests/test_stack.py b/pydatastructs/miscellaneous_data_structures/tests/test_stack.py
index 2522089be..d8ee561ec 100644
--- a/pydatastructs/miscellaneous_data_structures/tests/test_stack.py
+++ b/pydatastructs/miscellaneous_data_structures/tests/test_stack.py
@@ -4,22 +4,17 @@
def test_Stack():
- s = Stack(maxsize=3, top=0)
+ s = Stack()
s.push(1)
s.push(2)
s.push(3)
- assert s.top == 3
+ assert s.peek == 3
assert str(s) == '[1, 2, 3]'
- assert raises(ValueError, lambda: s.push(4))
assert s.pop() == 3
assert s.pop() == 2
assert s.pop() == 1
- assert s.top == 0
- assert raises(ValueError, lambda: s.pop())
- assert raises(ValueError, lambda: Stack())
- assert raises(TypeError, lambda: Stack(maxsize=8, top=3.5))
- assert raises(ValueError, lambda: Stack(maxsize=5, top=0, items=[1, 2, 3]))
- assert raises(ValueError, lambda: Stack(maxsize=5, top=0,
- items=OneDimensionalArray(int, 6)))
- assert raises(NotImplementedError, lambda: Stack(implementation='',
- maxsize=5, top=0))
+ assert s.is_empty is True
+ assert raises(ValueError, lambda : s.pop())
+ _s = Stack(items=[1, 2, 3])
+ assert str(_s) == '[1, 2, 3]'
+ assert raises(NotImplementedError, lambda: Stack(implementation=''))
diff --git a/pydatastructs/trees/binary_trees.py b/pydatastructs/trees/binary_trees.py
index 3191d6a86..91fb96528 100644
--- a/pydatastructs/trees/binary_trees.py
+++ b/pydatastructs/trees/binary_trees.py
@@ -653,7 +653,7 @@ def _pre_order(self, node):
"""
visit = []
tree, size = self.tree.tree, self.tree.size
- s = Stack(maxsize=size)
+ s = Stack()
s.push(node)
while not s.is_empty:
node = s.pop()
@@ -671,7 +671,7 @@ def _in_order(self, node):
"""
visit = []
tree, size = self.tree.tree, self.tree.size
- s = Stack(maxsize=size)
+ s = Stack()
while not s.is_empty or node is not None:
if node is not None:
s.push(node)
@@ -689,7 +689,7 @@ def _post_order(self, node):
"""
visit = []
tree, size = self.tree.tree, self.tree.size
- s = Stack(maxsize=size)
+ s = Stack()
s.push(node)
last = OneDimensionalArray(int, size)
last.fill(False)