Merge branch 'master' into master

Author: yanglbme

src/main/java/com/thealgorithms/datastructures/graphs/A_Star.java

@@ -16,7 +16,7 @@ private static class Graph {
         public Graph(int size) {
             this.graph = new ArrayList<>();
             for (int i = 0; i < size; i++) {
-                this.graph.set(i, new ArrayList<>());
+                this.graph.add(new ArrayList<>());
             }
         }
 

src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java

@@ -4,41 +4,12 @@
 //Link to the concept: (https://en.wikipedia.org/wiki/Circular_buffer)
 public class CircularQueue {
 
-    public static void main(String[] args) {
-        circularQueue cq = new circularQueue(5);
-        System.out.println(cq.isEmpty());
-        System.out.println(cq.isFull());
-        cq.enQueue(1);
-        cq.enQueue(2);
-        cq.enQueue(3);
-        cq.enQueue(4);
-        cq.enQueue(5);
-
-        System.out.println(cq.deQueue());
-        System.out.println(cq.deQueue());
-        System.out.println(cq.deQueue());
-        System.out.println(cq.deQueue());
-        System.out.println(cq.deQueue());
-        System.out.println(cq.isFull());
-        System.out.println(cq.isEmpty());
-        cq.enQueue(6);
-        cq.enQueue(7);
-        cq.enQueue(8);
-        System.out.println(cq.peek());
-        System.out.println(cq.peek());
-        cq.deleteQueue();
-
-    }
-}
-
-class circularQueue {
-
     int[] arr;
     int topOfQueue;
     int beginningOfQueue;
     int size;
 
-    public circularQueue(int size) {
+    public CircularQueue(int size) {
         arr = new int[size];
         topOfQueue = -1;
         beginningOfQueue = -1;
@@ -115,4 +86,30 @@ public void deleteQueue() {
         System.out.println("The Queue is deleted!");
     }
 
+
+    public static void main(String[] args) {
+        CircularQueue cq = new CircularQueue(5);
+        System.out.println(cq.isEmpty());
+        System.out.println(cq.isFull());
+        cq.enQueue(1);
+        cq.enQueue(2);
+        cq.enQueue(3);
+        cq.enQueue(4);
+        cq.enQueue(5);
+
+        System.out.println(cq.deQueue());
+        System.out.println(cq.deQueue());
+        System.out.println(cq.deQueue());
+        System.out.println(cq.deQueue());
+        System.out.println(cq.deQueue());
+        System.out.println(cq.isFull());
+        System.out.println(cq.isEmpty());
+        cq.enQueue(6);
+        cq.enQueue(7);
+        cq.enQueue(8);
+        System.out.println(cq.peek());
+        System.out.println(cq.peek());
+        cq.deleteQueue();
+
+    }
 }

src/main/java/com/thealgorithms/maths/BinomialCoefficient.java

@@ -0,0 +1,46 @@
+package com.thealgorithms.maths;
+
+/*
+ * Java program for Binomial Cofficients
+ * Binomial Cofficients: A binomial cofficient C(n,k) gives number ways
+ * in which k objects can be chosen from n objects.
+ * Wikipedia: https://en.wikipedia.org/wiki/Binomial_coefficient
+ * 
+ * Author: Akshay Dubey (https://github.com/itsAkshayDubey)
+ * 
+ * */
+
+public class BinomialCoefficient {
+	
+	/**
+     * This method returns the number of ways in which k objects can be chosen from n objects
+     *
+     * @param total_objects Total number of objects
+     * @param no_of_objects Number of objects to be chosen from total_objects
+     * @return number of ways in which no_of_objects objects can be chosen from total_objects objects
+     */
+	
+	static int binomialCoefficient(int total_objects, int no_of_objects) {
+		
+		//Base Case
+		if(no_of_objects > total_objects) {
+			return 0;
+		}
+		
+		//Base Case
+		if(no_of_objects == 0 || no_of_objects == total_objects) {
+			return 1;
+		}
+		
+		//Recursive Call
+		return binomialCoefficient(total_objects - 1, no_of_objects - 1)
+				+ binomialCoefficient(total_objects - 1, no_of_objects);
+	}
+	
+	public static void main(String[] args) {
+		System.out.println(binomialCoefficient(20,2));
+		
+		//Output: 190
+	}
+
+}