Merge pull request #474 from vlx01/vlx01/bitonic-sort

adding bitonic sort

Author: geekquad

java/sorting/bitonic_sort.java

@@ -0,0 +1,77 @@
+// Bitonic Sort
+//this program works when size of input is power of 2. 
+public class BitonicSort 
+{ 
+static void exchange(int arr[], int i, int j, boolean d) 
+{ 
+ int temp; 
+ if (d==(arr[i]>arr[j])) 
+ { 
+ temp = arr[i]; 
+ arr[i] = arr[j]; 
+ arr[j] = temp; 
+ } 
+} 
+/* The sequence to be sorted starts at
+index position low (l), the parameter c is the number
+of elements to be sorted.*/
+static void bitonicMerge(int arr[], int l, int c, boolean d) 
+{ 
+ int k,i; 
+ if (c>1) 
+ { 
+ k = c/2; 
+ for (i=l; i<l+k; i++) 
+ exchange(arr, i, i+k, d); 
+ bitonicMerge(arr, l, k, d); 
+ bitonicMerge(arr, l+k, k, d); 
+ } 
+} 
+static void bitonicSort(int arr[],int l, int c, boolean d) 
+{ 
+ int k; 
+ if (c>1) 
+ { 
+ k = c/2; 
+ // sort in ascending order since dir here is 1
+ bitonicSort(arr, l, k, true); 
+
+ // sort in descending order since dir here is 0
+ bitonicSort(arr, l+k, k, false); 
+
+ // Will merge whole sequence in ascending order since dir=1.
+ bitonicMerge(arr,l, c, d); 
+ } 
+} 
+ /*Caller of bitonicSort for sorting the entire array
+ of length N in ASCENDING order */ 
+
+static void sort(int arr[], int n, boolean order) 
+{ 
+ bitonicSort(arr,0, n, order); 
+} 
+
+ /* A utility function to print array of size n */
+ static void printArray(int arr[])
+ {
+ int n = arr.length;
+ for (int i=0; i<n; ++i)
+ System.out.print(arr[i] + " ");
+ System.out.println();
+ }
+
+// Driver Code
+
+public static void main(String[] args) 
+{ 
+ int arr[]= {1, 10, 2, 3, 1, 23, 45, 21}; 
+ int n = arr.length; 
+ int i; 
+ boolean order = true; 
+ sort(arr, n, order); 
+ 
+ System.out.println("Sorted array: \n"); 
+ for (i=0; i<n; i++) 
+ System.out.println(arr[i]); 
+} 
+}