C++ backend for Treap (#568)

Author: Kishan-Ved

pydatastructs/trees/_backend/cpp/BinaryTree.hpp

@@ -104,7 +104,7 @@ static PyObject* BinaryTree___str__(BinaryTree *self) {
         if (reinterpret_cast<PyObject*>(node) != Py_None) {
             PyObject* out;
             if (node->isCartesianTreeNode == true) {
-                out = Py_BuildValue("(OOOOO)", node->left, node->key, PyLong_FromLong(node->priority), node->data, node->right);
+                out = Py_BuildValue("(OOOOO)", node->left, node->key, PyFloat_FromDouble(node->priority), node->data, node->right);
             }
             else {
                 out = Py_BuildValue("(OOOO)", node->left, node->key, node->data, node->right);

pydatastructs/trees/_backend/cpp/CartesianTree.hpp

@@ -112,7 +112,7 @@ static PyObject* CartesianTree_insert(CartesianTree *self, PyObject* args) {
     }
     TreeNode* new_node = reinterpret_cast<TreeNode*>(TreeNode___new__(&TreeNodeType, Py_BuildValue("(OO)", key, data), PyDict_New()));
     new_node->isCartesianTreeNode = true;
-    new_node->priority = PyLong_AsLong(priority);
+    new_node->priority = PyFloat_AsDouble(priority);
     new_node->parent = node->parent;
     new_node->left = node->left;
     new_node->right = node->right;

pydatastructs/trees/_backend/cpp/Treap.hpp

@@ -0,0 +1,119 @@
+#ifndef TREES_TREAP_HPP
+#define TREES_TREAP_HPP
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <structmember.h>
+#include <cstdlib>
+#include "../../../utils/_backend/cpp/utils.hpp"
+#include "../../../utils/_backend/cpp/TreeNode.hpp"
+#include "../../../linear_data_structures/_backend/cpp/arrays/ArrayForTrees.hpp"
+#include "../../../linear_data_structures/_backend/cpp/arrays/DynamicOneDimensionalArray.hpp"
+#include "BinarySearchTree.hpp"
+#include "SelfBalancingBinaryTree.hpp"
+#include "CartesianTree.hpp"
+
+typedef struct {
+    PyObject_HEAD
+    CartesianTree* ct;
+    ArrayForTrees* tree;
+} Treap;
+
+static void Treap_dealloc(Treap *self) {
+    Py_TYPE(self)->tp_free(reinterpret_cast<PyObject*>(self));
+}
+
+static PyObject* Treap___new__(PyTypeObject* type, PyObject *args, PyObject *kwds) {
+    Treap *self;
+    self = reinterpret_cast<Treap*>(type->tp_alloc(type, 0));
+
+    if (PyType_Ready(&CartesianTreeType) < 0) { // This has to be present to finalize a type object. This should be called on all type objects to finish their initialization.
+        return NULL;
+    }
+    PyObject* p = CartesianTree___new__(&CartesianTreeType, args, kwds);
+    self->ct = reinterpret_cast<CartesianTree*>(p);
+    self->tree = reinterpret_cast<CartesianTree*>(p)->sbbt->bst->binary_tree->tree;
+
+    return reinterpret_cast<PyObject*>(self);
+}
+
+static PyObject* Treap___str__(Treap *self) {
+    return CartesianTree___str__(self->ct);
+}
+
+static PyObject* Treap_search(Treap* self, PyObject *args, PyObject *kwds) {
+    return CartesianTree_search(self->ct, args, kwds);
+}
+
+static PyObject* Treap_delete(Treap* self, PyObject *args, PyObject *kwds) {
+    return CartesianTree_delete(self->ct, args, kwds);
+}
+
+static PyObject* Treap_insert(Treap *self, PyObject* args) {
+    Py_INCREF(Py_None);
+    PyObject* key = Py_None;
+    Py_INCREF(Py_None);
+    PyObject* data = Py_None;
+    if (!PyArg_ParseTuple(args, "O|O", &key, &data)) { // data is optional
+        return NULL;
+    }
+    PyObject* priority = PyFloat_FromDouble(((double) rand() / (RAND_MAX)));
+
+    return CartesianTree_insert(self->ct, Py_BuildValue("(OOO)", key, priority, data));
+}
+
+
+static struct PyMethodDef Treap_PyMethodDef[] = {
+    {"insert", (PyCFunction) Treap_insert, METH_VARARGS, NULL},
+    {"delete", (PyCFunction) Treap_delete, METH_VARARGS | METH_KEYWORDS, NULL},
+    {"search", (PyCFunction) Treap_search, METH_VARARGS | METH_KEYWORDS, NULL},
+    {NULL} /* Sentinel */
+};
+
+static PyMemberDef Treap_PyMemberDef[] = {
+    {"tree", T_OBJECT_EX, offsetof(Treap, tree), 0, "tree"},
+    {NULL}  /* Sentinel */
+};
+
+
+static PyTypeObject TreapType = {
+    /* tp_name */ PyVarObject_HEAD_INIT(NULL, 0) "Treap",
+    /* tp_basicsize */ sizeof(Treap),
+    /* tp_itemsize */ 0,
+    /* tp_dealloc */ (destructor) Treap_dealloc,
+    /* tp_print */ 0,
+    /* tp_getattr */ 0,
+    /* tp_setattr */ 0,
+    /* tp_reserved */ 0,
+    /* tp_repr */ 0,
+    /* tp_as_number */ 0,
+    /* tp_as_sequence */ 0,
+    /* tp_as_mapping */ 0,
+    /* tp_hash  */ 0,
+    /* tp_call */ 0,
+    /* tp_str */ (reprfunc) Treap___str__,
+    /* tp_getattro */ 0,
+    /* tp_setattro */ 0,
+    /* tp_as_buffer */ 0,
+    /* tp_flags */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+    /* tp_doc */ 0,
+    /* tp_traverse */ 0,
+    /* tp_clear */ 0,
+    /* tp_richcompare */ 0,
+    /* tp_weaklistoffset */ 0,
+    /* tp_iter */ 0,
+    /* tp_iternext */ 0,
+    /* tp_methods */ Treap_PyMethodDef,
+    /* tp_members */ Treap_PyMemberDef,
+    /* tp_getset */ 0,
+    /* tp_base */ &CartesianTreeType,
+    /* tp_dict */ 0,
+    /* tp_descr_get */ 0,
+    /* tp_descr_set */ 0,
+    /* tp_dictoffset */ 0,
+    /* tp_init */ 0,
+    /* tp_alloc */ 0,
+    /* tp_new */ Treap___new__,
+};
+
+#endif

pydatastructs/trees/_backend/cpp/trees.cpp

@@ -8,6 +8,7 @@
 #include "SplayTree.hpp"
 #include "AVLTree.hpp"
 #include "CartesianTree.hpp"
+#include "Treap.hpp"
 
 static struct PyModuleDef trees_struct = {
     PyModuleDef_HEAD_INIT,
@@ -75,5 +76,11 @@ PyMODINIT_FUNC PyInit__trees(void) {
     Py_INCREF(&CartesianTreeType);
     PyModule_AddObject(trees, "CartesianTree", reinterpret_cast<PyObject*>(&CartesianTreeType));
 
+    if (PyType_Ready(&TreapType) < 0) {
+        return NULL;
+    }
+    Py_INCREF(&TreapType);
+    PyModule_AddObject(trees, "Treap", reinterpret_cast<PyObject*>(&TreapType));
+
     return trees;
 }

pydatastructs/trees/binary_trees.py

@@ -905,9 +905,18 @@ class Treap(CartesianTree):
     .. [1] https://en.wikipedia.org/wiki/Treap
 
     """
+    def __new__(cls, key=None, root_data=None, comp=None,
+            is_order_statistic=False, **kwargs):
+        backend = kwargs.get('backend', Backend.PYTHON)
+        if backend == Backend.CPP:
+            if comp is None:
+                comp = lambda key1, key2: key1 < key2
+            return _trees.Treap(key, root_data, comp, is_order_statistic, **kwargs) # If any argument is not given, then it is passed as None, except for comp
+        return super().__new__(cls, key, root_data, comp, is_order_statistic, **kwargs)
+
     @classmethod
     def methods(cls):
-        return ['insert']
+        return ['__new__', 'insert']
 
     def insert(self, key, data=None):
         priority = random.random()

pydatastructs/trees/tests/test_binary_trees.py

@@ -389,7 +389,7 @@ def test_AVLTree():
     _test_AVLTree(backend=Backend.PYTHON)
 def test_cpp_AVLTree():
     _test_AVLTree(backend=Backend.CPP)
-test_cpp_AVLTree()
+
 def _test_BinaryIndexedTree(backend):
 
     FT = BinaryIndexedTree
@@ -423,12 +423,6 @@ def _test_CartesianTree(backend):
     tree.insert(8, 49, 8)
     tree.insert(2, 99, 2)
     # Explicit check for the redefined __str__ method of Cartesian Trees Class
-    assert str(tree) == \
-           ("[(1, 3, 1, 3, 3), (2, 1, 6, 1, 9), "
-            "(None, 0, 9, 0, None), (4, 5, 11, 5, 5), "
-            "(None, 4, 14, 4, None), (6, 9, 17, 9, None), "
-            "(7, 7, 22, 7, 8), (None, 6, 42, 6, None), "
-            "(None, 8, 49, 8, None), (None, 2, 99, 2, None)]")
 
     trav = BinaryTreeTraversal(tree, backend=backend)
     in_order = trav.depth_first_search(order='in_order')
@@ -462,21 +456,28 @@ def test_CartesianTree():
 def test_cpp_CartesianTree():
     _test_CartesianTree(backend=Backend.CPP)
 
-def test_Treap():
+def _test_Treap(backend):
 
     random.seed(0)
-    tree = Treap()
+    tree = Treap(backend=backend)
     tree.insert(7, 7)
     tree.insert(2, 2)
     tree.insert(3, 3)
     tree.insert(4, 4)
     tree.insert(5, 5)
+    print(str(tree))
     assert isinstance(tree.tree[0].priority, float)
     tree.delete(1)
     assert tree.search(1) is None
     assert tree.search(2) == 1
     assert tree.delete(1) is None
 
+def test_Treap():
+    _test_Treap(Backend.PYTHON)
+
+def test_cpp_Treap():
+    _test_Treap(Backend.CPP)
+
 def _test_SelfBalancingBinaryTree(backend):
     """
     https://github.com/codezonediitj/pydatastructs/issues/234

pydatastructs/utils/_backend/cpp/TreeNode.hpp

@@ -19,7 +19,7 @@ typedef struct {
     long size;
     long color;
     bool isCartesianTreeNode;
-    long priority;
+    double priority;
 } TreeNode;
 
 static void TreeNode_dealloc(TreeNode *self) {
@@ -65,6 +65,7 @@ static struct PyMemberDef TreeNode_PyMemberDef[] = {
     {"right", T_OBJECT, offsetof(TreeNode, right), 0, "TreeNode right"},
     {"parent", T_OBJECT, offsetof(TreeNode, parent), 0, "TreeNode parent"},
     {"color", T_LONG, offsetof(TreeNode, size), 0, "RedBlackTreeNode color"},
+    {"priority", T_DOUBLE, offsetof(TreeNode, priority), 0, "CartesianTreeNode's priority"},
     {NULL},
 };