add and remove working

data_structures/__init__.py

@@ -6,4 +6,4 @@
 __email__ = 'narenuday595@gmail.com'
 __version__ = '0.1.0'
 
-from . import stack, linked_list, queue, bst, graph
+from . import stack, linked_list, queue, bst, graph, dynamic_arrays

data_structures/dynamic_arrays.py

@@ -6,15 +6,50 @@
 # - get, set, pushback, remove, size
 
 class DynamicArray:
-    def __init__(self, size=4):
-        self.capacity = size
+    def __init__(self, capacity=4):
+        self.capacity = capacity
+        self._size = 0
         self.array = [None] * self.capacity
+        self._increaseFactor = 2
 
     def get(self, i):
         return self.array[i]
 
     def set(self, i, val):
         self.array[i] = val
 
-    def pushback(self, i, val):
-        pass
+    def pushback(self, val):
+        if self.capacity == self._size:
+            # resize the array
+            _array = [None] * (self.capacity * self._increaseFactor)
+            for i in range(self.capacity):
+                _array[i] = self.array[i]
+            self.array = _array
+            del _array
+
+            self.capacity *= self._increaseFactor
+
+        self.array[self._size] = val
+        self._size +=  1
+
+    @property
+    def size(self):
+        return self._size
+
+    def remove(self, i):
+        # Remove the element and adjust the array.
+        while i < self._size:
+            self.array[i] = self.array[i+1]
+            print(i, self.array[i])
+            i = i + 1
+        self._size = self._size - 1
+
+    def __str__(self):
+        s = '{}, '
+        out = ''
+        for i in range(self._size):
+            out += s.format(self.array[i])
+            if i is None:
+                break
+
+        return '[{}]'.format(out.strip())

tests/context.py

@@ -0,0 +1,3 @@
+import os
+import sys
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))

tests/test_data_structures_bst.py

@@ -1,8 +1,4 @@
 import unittest
 
-
-
-
-
 if __name__ == '__main__':
     unittest.main()

tests/test_dynamic_arrays.py

@@ -1,5 +1,45 @@
+import context
+
 import unittest
 
+from data_structures.dynamic_arrays import DynamicArray
+
+
 class DynamicArrays(unittest.TestCase):
     def test__init(self):
-        pass
+        array = DynamicArray()
+        for i in range(0,4):
+            array.pushback(i)
+
+        self.assertEqual(array.size, 4)
+        self.assertEqual(array.capacity, 4)
+
+    def test_pushback(self):
+        array = DynamicArray()
+
+        for i in range(0, 10):
+            array.pushback(i)
+
+        self.assertEqual(array.size, 10)
+        self.assertEqual(array.capacity, 16)
+
+    def test_remove(self):
+        array = DynamicArray()
+
+        for i in range(0, 10):
+            array.pushback(i)
+
+        self.assertEqual(array.size, 10)
+        self.assertEqual(array.capacity, 16)
+
+        array.remove(4)
+        self.assertEqual(str(array), '[0, 1, 2, 3, 5, 6, 7, 8, 9,]')
+
+        array.remove(4)
+        self.assertEqual(str(array), '[0, 1, 2, 3, 6, 7, 8, 9,]')
+
+        array.remove(0)
+        self.assertEqual(str(array), '[1, 2, 3, 6, 7, 8, 9,]')
+
+        array.remove(6)
+        self.assertEqual(str(array), '[1, 2, 3, 6, 7, 8,]')