extract_min has been tested.

Author: arunkumaraqm

FibHeap.py

@@ -1,6 +1,10 @@
 from collections import defaultdict
 INFINITY = float('inf')
-teststr = "loud"##
+teststr = "silent"## Remember to use global when you use this.
+def show(something):
+if teststr == "loud": print(something)
+def struc(something):
+if teststr == "loud": something.print_heap()
 
 class FibHeapNode:
 """
@@ -42,8 +46,12 @@ def print_tree(self, tabwidth = 0):
 An asterisk after the value indicates that this node is marked
 """
 
-print(tabwidth*" ", self.ele, '*' if self.mark else '', sep = "")
-input()#
+if teststr == "silent": 
+print(tabwidth*" ", self.ele, '*' if self.mark else '', sep = "")
+elif teststr == "loud":
+print(tabwidth*" ", end = " ")
+show((self.ele, id(self)))
+#input()#
 for childtree in self.children_generator():
 childtree.print_tree(tabwidth + 1)
 
@@ -128,7 +136,7 @@ def __root_list_generator(self):
 
 
 def print_heap(self):
-print("head and minnode", self.head, self.min_node)
+print("### head and minnode", self.head, self.min_node)
 for root in self.__root_list_generator():
 #print(root, '(', root.left, root.right, root.child,')')
 root.print_tree()
@@ -152,7 +160,7 @@ def __consolidate(self):
 
 def merging_trees(cur_root):
 other_root = self.degree_tree_map[cur_root.rank]
-#print(other_root)#
+
 
 if other_root is None:
 self.degree_tree_map[cur_root.rank] = cur_root
@@ -170,49 +178,54 @@ def merging_trees(cur_root):
 
 merging_trees(combined_root)
 
-self.min_node = self.head
-
 for cur_root in self.__root_list_generator():
-# print(cur_root, self.head, end=" ")
-
-if cur_root < self.min_node:
-self.min_node = cur_root
-
 merging_trees(cur_root)
 
+ # Maybe this can be done earlier.
+try:
+roots_iter = filter(lambda node: node is not None, self.degree_tree_map.values())
+self.min_node = min(roots_iter) 
+"""
+Note: This does not have to be the node of the first_occurence of the minimum ele
+since dictionaries are not ordered by their key.
+This means you could have a node with ele 4 as head and another node with ele 4 as tail
+and self.min_node could point to the latter.
+"""
+except ValueError as err:
+if str(err) == "min() arg is an empty sequence":
+self.min_node = None
+else: 
+raise ValueError(err)
 
 def __attach(self, node1, node2):
 # Connecting node 1 and node 2 such that node 2 is at node 1's right side
 node1.right = node2
 node2.left = node1
 
-def __merge_lls(self, head_one, head_two, teststr = ""):
+def __merge_lls(self, head_one, head_two):
 # Merging two circular doubly linked lists and returning the new head.
 tail_one, tail_two = head_one.left, head_two.left
 self.__attach(tail_one, head_two)
 self.__attach(tail_two, head_one)
-if teststr != "silent": self.print_heap()
 return head_one
 
 def extract_min(self):
 if not self.head: 
 raise IndexError("Popping from an empty heap.")
 
 node_to_be_popped = self.min_node
+
 if node_to_be_popped.child: 
 # If the node to be popped has any children,
 # Add them to the root list.
 self.__merge_lls(self.head, node_to_be_popped.child)
 
-if teststr == "loud": self.print_heap()#
-
-if node_to_be_popped is self.head: self.head = self.head.right # Test this. 
 self.__remove_node(node_to_be_popped)
 self.__consolidate()
 
 return node_to_be_popped.ele
 
-def not_extract_min_test(mylist):
+def extract_min_test(mylist):
 heap = FibHeap()
 
 for i in mylist:
@@ -225,43 +238,21 @@ def not_extract_min_test(mylist):
 heap.extract_min()
 heap.print_heap()
 
-def extract_min_test(mylist):
-heap = FibHeap()
-
-for i in mylist:
-heap.insert(i)
-#print("After all insertions:")
-#heap.print_heap()#
-
-for x in range(4):
-#	print(f"After {x + 1}th extraction:")
-heap.extract_min("silent")
-#print("after 4th ex")
-#heap.print_heap()
-print("during 5th ex")
-heap.extract_min("loud")
-print("after 5th ex")
-heap.print_heap()
-#heap.extract_min()
-"""
-After 4th extraction:
-head and minnode 4 4
-4
- 7
- 4
- 4
- 8
- 8
- 9
- 10
-"""
+try: heap.extract_min()
+except IndexError as err:
+if str(err) == "Popping from an empty heap.":
+pass
+else: raise IndexError(err)
 
 extract_min_test_1 = lambda: extract_min_test([1, 2])
 extract_min_test_2 = lambda: extract_min_test([1, 2, 3, 4])
 extract_min_test_3 = lambda: extract_min_test([10, 20, 30, 40, 50, 60, 70, 80])
 extract_min_test_4 = lambda: extract_min_test([8, 8, 2, 4, 1, 4, 2, 9, 10, 4, 2, 7])
+extract_min_test_5 = lambda: extract_min_test([10])
+extract_min_test_6 = lambda: extract_min_test([20, 10, 40, 28, 46, 10, 35, 26, 83, 18, 32, 46])
+extract_min_test_7 = lambda: extract_min_test([])
 
-extract_min_test_4()
+extract_min_test_6()
 
 def _FibHeap__remove_node_test_1():
 heap = FibHeap()