From 363fe9c20a1dfd4a4a8443b9b6eb904edf3766cc Mon Sep 17 00:00:00 2001
From: hackgone <bishtpiyush17@gmail.com>
Date: Sat, 30 Oct 2021 18:30:42 +0530
Subject: [PATCH] added new algorithm in java

---
 JAVA/FibHeap.java | 146 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 JAVA/FibHeap.java

diff --git a/JAVA/FibHeap.java b/JAVA/FibHeap.java
new file mode 100644
index 0000000..6b0de53
--- /dev/null
+++ b/JAVA/FibHeap.java
@@ -0,0 +1,146 @@
+public class FibHeap {
+    public Node min;
+    public int numNodes;
+    
+    public FibHeap() {
+        this.min = null;
+        this.numNodes = 0;
+    }
+
+    public void insertNode(int key, int vertVal) {
+        Node x = new Node(key, vertVal);
+        this.min = mergeLists(this.min, x);
+        this.numNodes += 1;        
+    }
+
+    public void insertNode(Node x) {
+        // part of extract min function
+        this.min = mergeLists(this.min, x);
+    }
+
+    public Node mergeLists(Node a, Node b) {
+        if (a == null && b == null) 
+            return null;
+        
+        if (a == null) 
+            return b;
+        
+        if (b == null)
+            return a;
+        
+        Node temp = a.next;
+
+        a.next = b.next;
+        a.next.prev = a;
+
+        b.next = temp;
+        b.next.prev = b;
+
+        return (a.key < b.key) ? a : b;
+    }
+
+    public Node extractMin() {
+        if(this.min == null) {
+            System.out.println("Underflow");
+            return null;
+        }
+
+        else {
+            Node child = this.min.child;
+            if(child != null) {
+                while(child.next != child) {
+                    Node temp = child;
+                    child.next.prev = child.prev;
+                    child.prev.next = child.next;
+                    child = child.next;
+                    
+                    temp.next = temp;
+                    temp.prev = temp;
+                    temp.parent = null;
+
+                    insertNode(temp);
+                }
+                child.parent = null;
+                insertNode(child);
+            }
+            Node z = this.min;
+            if (z == z.next){
+                this.min = null;
+                return z;
+            }
+
+            else {
+                this.min = z.next;
+                z.next.prev = z.prev;
+                z.prev.next = z.next;
+                
+                z.next = z;
+                z.prev = z;
+
+                // consolidate()
+
+                return z;
+            }
+        }
+    }
+
+    public void consolidate() {
+        int D = (int) (Math.log(this.numNodes) / Math.log(2));
+        D += 1;
+
+        Node[] array = new Node[D];
+        for (Node i : array ) {
+            i = null;
+        }
+
+    }
+
+    public void printList(Node x) {
+        if (x == null) {
+            System.out.println("||");
+            return;
+        }
+
+        Node temp = x;
+        System.out.print(x.key + " --> ");
+        temp = temp.next;
+
+        while(temp != x){
+            System.out.print(temp.key + " --> ");
+            temp = temp.next;
+        }
+
+        System.out.println( "||");
+    }
+
+    public static void main(String[] args) {
+        FibHeap H = new FibHeap();
+        H.insertNode(1,0);
+        H.insertNode(2,0);
+        H.printList(H.min);
+
+        H.extractMin();
+        H.printList(H.min);
+
+        H.extractMin();
+        H.printList(H.min);
+    }
+}
+
+class Node {
+    public Node(int key, int vertVal) {
+        this.key = key;
+        this.vertVal = vertVal;
+        this.next = this;
+        this.prev = this;
+    }
+
+    public int key;
+    public int vertVal; // Value of vertex in graph
+    public Node child = null;
+    public Node parent = null;
+    public Node next = null;
+    public Node prev = null;
+    public boolean isMarked = false;
+    public int degree = 0;
+}
\ No newline at end of file