C++ backend for Cartesian Trees (#567)

pydatastructs/trees/_backend/cpp/BinaryTree.hpp

@@ -102,7 +102,13 @@ static PyObject* BinaryTree___str__(BinaryTree *self) {
         OneDimensionalArray* oda = self->tree->_one_dimensional_array;
         TreeNode* node = reinterpret_cast<TreeNode*>(oda->_data[i]);
         if (reinterpret_cast<PyObject*>(node) != Py_None) {
-            PyObject* out = Py_BuildValue("(OOOO)", node->left, node->key, node->data, node->right);
+            PyObject* out;
+            if (node->isCartesianTreeNode == true) {
+                out = Py_BuildValue("(OOOOO)", node->left, node->key, PyLong_FromLong(node->priority), node->data, node->right);
+            }
+            else {
+                out = Py_BuildValue("(OOOO)", node->left, node->key, node->data, node->right);
+            }
             Py_INCREF(out);
             PyList_SET_ITEM(list, i, out);
         }

pydatastructs/trees/_backend/cpp/BinaryTreeTraversal.hpp

@@ -17,6 +17,7 @@
 #include "RedBlackTree.hpp"
 #include "SplayTree.hpp"
 #include "AVLTree.hpp"
+#include "CartesianTree.hpp"
 
 typedef struct {
     PyObject_HEAD
@@ -48,13 +49,19 @@ static PyObject* BinaryTreeTraversal___new__(PyTypeObject* type, PyObject *args,
     if (PyType_Ready(&AVLTreeType) < 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;
     }
+    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;
+    }
 
     if (PyObject_IsInstance(tree, (PyObject *)&SplayTreeType)) {
         self->tree = reinterpret_cast<SplayTree*>(tree)->sbbt->bst->binary_tree;
     }
     else if (PyObject_IsInstance(tree, (PyObject *)&AVLTreeType)) {
         self->tree = reinterpret_cast<AVLTree*>(tree)->sbbt->bst->binary_tree;
     }
+    else if (PyObject_IsInstance(tree, (PyObject *)&CartesianTreeType)) {
+        self->tree = reinterpret_cast<CartesianTree*>(tree)->sbbt->bst->binary_tree;
+    }
     else if (PyObject_IsInstance(tree, (PyObject *)&RedBlackTreeType)) {
         self->tree = reinterpret_cast<RedBlackTree*>(tree)->sbbt->bst->binary_tree;
     }

pydatastructs/trees/_backend/cpp/CartesianTree.hpp

@@ -0,0 +1,210 @@
+#ifndef TREES_CARTESIANTREE_HPP
+#define TREES_CARTESIANTREE_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"
+
+typedef struct {
+    PyObject_HEAD
+    SelfBalancingBinaryTree* sbbt;
+    ArrayForTrees* tree;
+} CartesianTree;
+
+static void CartesianTree_dealloc(CartesianTree *self) {
+    Py_TYPE(self)->tp_free(reinterpret_cast<PyObject*>(self));
+}
+
+static PyObject* CartesianTree___new__(PyTypeObject* type, PyObject *args, PyObject *kwds) {
+    CartesianTree *self;
+    self = reinterpret_cast<CartesianTree*>(type->tp_alloc(type, 0));
+
+    if (PyType_Ready(&SelfBalancingBinaryTreeType) < 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 = SelfBalancingBinaryTree___new__(&SelfBalancingBinaryTreeType, args, kwds);
+    self->sbbt = reinterpret_cast<SelfBalancingBinaryTree*>(p);
+    self->tree = reinterpret_cast<SelfBalancingBinaryTree*>(p)->bst->binary_tree->tree;
+
+    return reinterpret_cast<PyObject*>(self);
+}
+
+static PyObject* CartesianTree___str__(CartesianTree *self) {
+    return BinarySearchTree___str__(self->sbbt->bst);
+}
+
+static PyObject* CartesianTree_search(CartesianTree* self, PyObject *args, PyObject *kwds) {
+    return BinarySearchTree_search(self->sbbt->bst, args, kwds);
+}
+
+static PyObject* Cartesian_Tree__bubble_up(CartesianTree* self, PyObject *args) {
+    PyObject* node_idx = PyObject_GetItem(args, PyZero);
+    BinaryTree* bt = self->sbbt->bst->binary_tree;
+    TreeNode* node = reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)]);
+    PyObject* parent_idx = reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)])->parent;
+    TreeNode* parent = reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(parent_idx)]);
+
+    while ((node->parent != Py_None) && (parent->priority > node->priority)) {
+        if (parent->right == node_idx) {
+            SelfBalancingBinaryTree__left_rotate(self->sbbt, Py_BuildValue("OO", parent_idx, node_idx));
+        }
+        else {
+            SelfBalancingBinaryTree__right_rotate(self->sbbt, Py_BuildValue("OO", parent_idx, node_idx));
+        }
+        node = reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)]);
+        parent_idx = reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)])->parent;
+        if (parent_idx != Py_None) {
+            parent = reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(parent_idx)]);
+        }
+    }
+    if (node->parent == Py_None) {
+        reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)])->is_root = true;
+    }
+    Py_RETURN_NONE;
+}
+
+static PyObject* Cartesian_Tree__trickle_down(CartesianTree* self, PyObject *args) {
+    PyObject* node_idx = PyObject_GetItem(args, PyZero);
+    BinaryTree* bt = self->sbbt->bst->binary_tree;
+    TreeNode* node = reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)]);
+    while (node->left != Py_None || node->right != Py_None) {
+        if (node->left == Py_None) {
+            SelfBalancingBinaryTree__left_rotate(self->sbbt, Py_BuildValue("OO", node_idx, reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)])->right));
+        }
+        else if (node->right == Py_None) {
+            SelfBalancingBinaryTree__right_rotate(self->sbbt, Py_BuildValue("OO", node_idx, reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)])->left));
+        }
+        else if (reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node->left)])->priority < reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node->right)])->priority) {
+            SelfBalancingBinaryTree__right_rotate(self->sbbt, Py_BuildValue("OO", node_idx, reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)])->left));
+        }
+        else {
+            SelfBalancingBinaryTree__left_rotate(self->sbbt, Py_BuildValue("OO", node_idx, reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)])->right));
+        }
+        node = reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)]);
+    }
+    Py_RETURN_NONE;
+}
+
+static PyObject* CartesianTree_insert(CartesianTree *self, PyObject* args) {
+    Py_INCREF(Py_None);
+    PyObject* key = Py_None;
+    Py_INCREF(Py_None);
+    PyObject* priority = Py_None;
+    Py_INCREF(Py_None);
+    PyObject* data = Py_None;
+    if (!PyArg_ParseTuple(args, "OO|O", &key, &priority, &data)) { // data is optional
+        return NULL;
+    }
+    BinaryTree* bt = self->sbbt->bst->binary_tree;
+
+    SelfBalancingBinaryTree_insert(self->sbbt, Py_BuildValue("(OO)", key, data));
+    PyObject* node_idx = SelfBalancingBinaryTree_search(self->sbbt, Py_BuildValue("(O)", key), PyDict_New());
+    TreeNode* node = reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)]);
+    if (PyType_Ready(&TreeNodeType) < 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;
+    }
+    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->parent = node->parent;
+    new_node->left = node->left;
+    new_node->right = node->right;
+    bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)] = reinterpret_cast<PyObject*>(new_node);
+    if (node->is_root) {
+        reinterpret_cast<TreeNode*>(bt->tree->_one_dimensional_array->_data[PyLong_AsLong(node_idx)])->is_root = true;
+    }
+    else {
+        Cartesian_Tree__bubble_up(self, Py_BuildValue("(O)", node_idx));
+    }
+    Py_RETURN_NONE;
+}
+
+static PyObject* CartesianTree_delete(CartesianTree* self, PyObject *args, PyObject *kwds) {
+    Py_INCREF(Py_None);
+    PyObject* key = Py_None;
+    PyObject* balancing_info = PyZero;
+    static char* keywords[] = {"key","balancing_info", NULL};
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|O", keywords, &key, &balancing_info)) {
+        return NULL;
+    }
+    PyObject* node_idx = SelfBalancingBinaryTree_search(self->sbbt, Py_BuildValue("(O)", key), PyDict_New());
+    if (node_idx != Py_None) {
+        Cartesian_Tree__trickle_down(self, Py_BuildValue("(O)", node_idx));
+        PyObject* kwd_bal = PyDict_New();
+        PyDict_SetItemString(kwd_bal, "balancing_info", balancing_info);
+        return SelfBalancingBinaryTree_delete(self->sbbt, Py_BuildValue("(O)", key), kwd_bal);
+    }
+    Py_RETURN_NONE;
+}
+
+static PyObject* CartesianTree_root_idx(CartesianTree *self, void *closure) {
+    return self->sbbt->bst->binary_tree->root_idx;
+}
+
+
+static struct PyMethodDef CartesianTree_PyMethodDef[] = {
+    {"insert", (PyCFunction) CartesianTree_insert, METH_VARARGS, NULL},
+    {"delete", (PyCFunction) CartesianTree_delete, METH_VARARGS | METH_KEYWORDS, NULL},
+    {"search", (PyCFunction) CartesianTree_search, METH_VARARGS | METH_KEYWORDS, NULL},
+    {NULL} /* Sentinel */
+};
+
+static PyGetSetDef CartesianTree_GetterSetters[] = {
+    {"root_idx", (getter) CartesianTree_root_idx, NULL, "returns the index of the tree's root", NULL},
+    {NULL}  /* Sentinel */
+};
+
+static PyMemberDef CartesianTree_PyMemberDef[] = {
+    {"tree", T_OBJECT_EX, offsetof(CartesianTree, tree), 0, "tree"},
+    {NULL}  /* Sentinel */
+};
+
+
+static PyTypeObject CartesianTreeType = {
+    /* tp_name */ PyVarObject_HEAD_INIT(NULL, 0) "CartesianTree",
+    /* tp_basicsize */ sizeof(CartesianTree),
+    /* tp_itemsize */ 0,
+    /* tp_dealloc */ (destructor) CartesianTree_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) CartesianTree___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 */ CartesianTree_PyMethodDef,
+    /* tp_members */ CartesianTree_PyMemberDef,
+    /* tp_getset */ CartesianTree_GetterSetters,
+    /* tp_base */ &SelfBalancingBinaryTreeType,
+    /* tp_dict */ 0,
+    /* tp_descr_get */ 0,
+    /* tp_descr_set */ 0,
+    /* tp_dictoffset */ 0,
+    /* tp_init */ 0,
+    /* tp_alloc */ 0,
+    /* tp_new */ CartesianTree___new__,
+};
+
+#endif

pydatastructs/trees/_backend/cpp/trees.cpp

@@ -7,6 +7,7 @@
 #include "BinaryIndexedTree.hpp"
 #include "SplayTree.hpp"
 #include "AVLTree.hpp"
+#include "CartesianTree.hpp"
 
 static struct PyModuleDef trees_struct = {
     PyModuleDef_HEAD_INIT,
@@ -68,5 +69,11 @@ PyMODINIT_FUNC PyInit__trees(void) {
     Py_INCREF(&AVLTreeType);
     PyModule_AddObject(trees, "AVLTree", reinterpret_cast<PyObject*>(&AVLTreeType));
 
+    if (PyType_Ready(&CartesianTreeType) < 0) {
+        return NULL;
+    }
+    Py_INCREF(&CartesianTreeType);
+    PyModule_AddObject(trees, "CartesianTree", reinterpret_cast<PyObject*>(&CartesianTreeType));
+
     return trees;
 }

pydatastructs/trees/binary_trees.py

@@ -804,9 +804,18 @@ class CartesianTree(SelfBalancingBinaryTree):
 
     pydatastructs.trees.binary_trees.SelfBalancingBinaryTree
     """
+    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.CartesianTree(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 ['__str__', 'insert', 'delete']
+        return ['__new__', '__str__', 'insert', 'delete']
 
     def _bubble_up(self, node_idx):
         node = self.tree[node_idx]

pydatastructs/trees/tests/test_binary_trees.py

@@ -410,8 +410,8 @@ def test_BinaryIndexedTree():
 def test_cpp_BinaryIndexedTree():
     _test_BinaryIndexedTree(Backend.CPP)
 
-def test_CartesianTree():
-    tree = CartesianTree()
+def _test_CartesianTree(backend):
+    tree = CartesianTree(backend=backend)
     tree.insert(3, 1, 3)
     tree.insert(1, 6, 1)
     tree.insert(0, 9, 0)
@@ -430,7 +430,7 @@ def test_CartesianTree():
             "(7, 7, 22, 7, 8), (None, 6, 42, 6, None), "
             "(None, 8, 49, 8, None), (None, 2, 99, 2, None)]")
 
-    trav = BinaryTreeTraversal(tree)
+    trav = BinaryTreeTraversal(tree, backend=backend)
     in_order = trav.depth_first_search(order='in_order')
     pre_order = trav.depth_first_search(order='pre_order')
     assert [node.key for node in in_order] == [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
@@ -446,6 +446,7 @@ def test_CartesianTree():
     k = tree.search(1.5)
     assert tree.tree[tree.tree[k].parent].key == 3
     tree.delete(1.5)
+    assert tree.root_idx == 0
     tree.tree[tree.tree[tree.root_idx].left].key == 1
     tree.delete(8)
     assert tree.search(8) is None
@@ -455,6 +456,12 @@ def test_CartesianTree():
     assert tree.search(3) is None
     assert tree.delete(18) is None
 
+def test_CartesianTree():
+    _test_CartesianTree(backend=Backend.PYTHON)
+
+def test_cpp_CartesianTree():
+    _test_CartesianTree(backend=Backend.CPP)
+
 def test_Treap():
 
     random.seed(0)

pydatastructs/utils/_backend/cpp/TreeNode.hpp

@@ -18,6 +18,8 @@ typedef struct {
     PyObject* parent;
     long size;
     long color;
+    bool isCartesianTreeNode;
+    long priority;
 } TreeNode;
 
 static void TreeNode_dealloc(TreeNode *self) {
@@ -42,6 +44,7 @@ static PyObject* TreeNode___new__(PyTypeObject* type, PyObject *args, PyObject *
     self->size = 1;
     self->is_root = false;
     self->color = 1;
+    self->isCartesianTreeNode = false;
 
     return reinterpret_cast<PyObject*>(self);
 }