Add Bucket Sort Algorithm

Fixes TheAlgorithms#96

Author: YJDave

Sorts/BucketSort.java

@@ -0,0 +1,159 @@
+/**
+ * 
+ * Bucket Sort Algorithm
+ * 
+ * @author yashashvi (github.com/YJDave)
+ * 
+ */
+
+
+/**
+ * Definition for Bucket Sort:
+ * 		Wikipedia: https://en.wikipedia.org/wiki/Bucket_sort
+ * 		Bucket sort, or bin sort, is a sorting algorithm that works by distributing the elements of an array into a number of buckets. 
+ * 		Each bucket is then sorted individually, either using a different sorting algorithm, or by recursively applying the bucket sorting algorithm.
+ * 
+ * Time complexity:
+ * 		n: length of input sequence
+ * 		k: number of buckets
+ * 		Average case: o(n+k)
+ * 		Worst case: o(n^2)
+ * 
+ */
+
+
+/**
+ * Implementation of Bucket Sort:
+ * 		1. Create and Initialize all Buckets
+ * 		2(i). Take input from user (any unsorted numbers)
+ * 		2(ii). Insert this numbers into specific Bucket according to HashFunction 
+ * 			(we use here HashFunction to find that in which Bucket number should be added)
+ * 			(you can use your custom HashFunction depending on input data's property)
+ * 		
+ *		3. Sort all Bucket (you can any sorting algorithm, here I have used Insertion Sort)
+ * 		4. Place sorted no into SortedArray from Bucket
+ * 		5. Print SortedArray
+ * 
+ *  Data-structure used:
+ *  	Array: for storing sorted and unsorted numbers
+ *  	Double Dimentional Array: for storing Buckets 
+ *			(I have used double dimenstional array for simple implementation but,
+ *  		If you want you can use linked list for storing buckets, for efficient usage of memory)
+ *  	
+ */
+
+
+
+import java.util.Scanner;
+
+public class BucketSort {
+	
+	
+	public static void main(String[] args) {
+	
+		int MaxBuckets = 10;
+
+		
+		System.out.println("Sort numbers using Bucket Sort Alogrithm");
+
+		Scanner input = new Scanner(System.in);
+		System.out.print("Enter total no of input: ");
+		int totalNo = input.nextInt();
+
+		//		1. Create and Initialize all Buckets
+		
+		int[][] Buckets = new int[MaxBuckets][totalNo+1];
+		System.out.println(totalNo+1);
+		// we use Buckets[0][*] for storing array top
+		// intialize it to 0
+		
+		for(int i=0;i<MaxBuckets;i++)
+			Buckets[i][0] = 1;
+
+		//		2(i). Take input from user (any unsorted numbers)
+		
+		System.out.println("Enter all no:");
+
+		int[] inputArray = new int[totalNo];
+		int inputIndex = 0;
+
+		for(int i=0;i<totalNo;i++) {
+			
+			int no = input.nextInt();
+			inputArray[inputIndex++] = no;
+		}
+		input.close();
+
+		//		2(ii). Insert this numbers into specific Bucket
+
+		for(int i=0;i<totalNo;i++) {
+			// System.out.println("\n"+"Deciding for no: "+inputArray[i]);
+			int hashKey = HashFunction(inputArray[i]);
+			int top = Buckets[hashKey][0];
+
+			// System.out.println("Hash key is: "+hashKey+" and top is: "+top+" so we will store no at top and increase top");
+			Buckets[hashKey][top] = inputArray[i];
+			Buckets[hashKey][0] = top+1;
+
+			// System.out.println("So our Bucket is: +"+"\n"+ "Bucket["+hashKey+"]["+0+"] = "+Buckets[hashKey][0]+" and "+"Bucket["+hashKey+"]["+top+"] = "+Buckets[hashKey][top]);
+
+		}
+		
+
+		//		3. Sort all Bucket (you can any sorting algorithm, here I have used Insertion Sort)
+
+		for(int i=0;i<MaxBuckets;i++) {	
+			int top = Buckets[i][0];
+			
+			// System.out.println("Sorting Bucket no:"+i);
+		    for(int k=1;k<top-1;k++) {
+		        int j = k +1;
+		        int temp = Buckets[i][j];
+		        while( k>0 && Buckets[i][k]>temp) {
+		        	Buckets[i][k+1] = Buckets[i][k];
+		            k--;
+		        }
+		        Buckets[i][k+1] = temp;
+		    }
+		}
+		
+		for(int i=0;i<MaxBuckets;i++) {
+			int top = Buckets[i][0];
+			for(int j=0;j<top;j++) {
+				System.out.println("Bucket["+i+"]["+j+"] = "+Buckets[i][j]);
+			}
+		}
+
+		//		4. Place sorted no into SortedArray from Bucket
+		
+		int[] SortedArray = new int[totalNo];
+		int sortedIndex=0;
+
+		for(int i=0;i<MaxBuckets;i++) {
+			int top = Buckets[i][0];
+			for(int j=1;j<top;j++) {
+				SortedArray[sortedIndex++] = Buckets[i][j];
+			}
+		}
+		
+		
+		//		5. Print SortedArray
+		
+		System.out.println("Sorted Array is: ");
+		for(int i=0;i<totalNo;i++)
+			System.out.print(SortedArray[i]+", ");
+
+	}
+	
+	public static int HashFunction(int no) {
+		
+		int Key = no/10;
+		if (Key>9)
+			Key=9;
+		// System.out.println(Key);
+		return Key;
+		
+	}
+
+	
+}