Added Fibonacci_Heap for DSA

Author: imSanko

data_structures/heap/fibonacci_heap.py

@@ -0,0 +1,101 @@
+class FibonacciNode:
+    def __init__(self, key):
+        self.key = key
+        self.children = []
+        self.marked = False
+        self.degree = 0
+        self.parent = None
+
+class FibonacciHeap:
+    def __init__(self):
+        self.trees = []
+        self.least = None
+        self.count = 0
+
+    def insert(self, key):
+        new_node = FibonacciNode(key)
+        self.trees.append(new_node)
+        self.count += 1
+        if self.least is None or key < self.least.key:
+            self.least = new_node
+
+    def extract_min(self):
+        if self.count == 0:
+            raise ValueError("Heap is empty")
+
+        min_node = self.least
+        self.trees.remove(min_node)
+
+        for child in min_node.children:
+            child.parent = None
+            self.trees.append(child)
+
+        self.count -= 1
+
+        if self.least is min_node:
+            self.least = None
+            for node in self.trees:
+                if self.least is None or node.key < self.least.key:
+                    self.least = node
+
+        self.consolidate()
+        return min_node.key
+
+    def consolidate(self):
+        degree_counts = [None] * (2 * len(self.trees))
+
+        for node in self.trees[:]:
+            degree = node.degree
+            while degree_counts[degree] is not None:
+                other_node = degree_counts[degree]
+                if node.key > other_node.key:
+                    node, other_node = other_node, node  # Swap nodes
+                self.link(other_node, node)
+                degree_counts[degree] = None
+                degree += 1
+            degree_counts[degree] = node
+
+        self.trees = [node for node in degree_counts if node is not None]
+
+    def link(self, node1, node2):
+        self.trees.remove(node2)
+        node1.children.append(node2)
+        node2.parent = node1
+        node1.degree += 1
+        node2.marked = False
+
+    def decrease_key(self, node, new_key):
+        if new_key > node.key:
+            raise ValueError("New key must be less than or equal to old key")
+
+        node.key = new_key
+
+        if node == self.least:
+            self.update_least()
+
+        parent = node.parent
+        if parent is not None and node.key < parent.key:
+            self.cut(node, parent)
+            self.cascading_cut(parent)
+
+    def cut(self, node, parent):
+        parent.children.remove(node)
+        parent.degree -= 1
+        self.trees.append(node)
+        node.parent = None
+        node.marked = False
+
+    def cascading_cut(self, node):
+        parent = node.parent
+        if parent is not None:
+            if not node.marked:
+                node.marked = True
+            else:
+                self.cut(node, parent)
+                self.cascading_cut(parent)
+
+    def update_least(self):
+        self.least = None
+        for node in self.trees:
+            if self.least is None or node.key < self.least.key:
+                self.least = node