add quickSort

Author: anmolpant

Diff for: Data Structures in Java/Level 1/Lecture 4 - Recursion 2/Recursion2_QuickSort.java

@@ -0,0 +1,54 @@
+
+public class Recursion2_QuickSort {
+	    
+	    
+	    public static int partition (int[] arr, int low, int high){
+	        int pivot = arr[high];
+	        //int i = (low-1);
+	        int count = low-1;
+	        for(int j = low; j<high; j++){
+	            
+	            if (arr[j]<pivot){
+	                count++;
+	                
+	                //swap arr[i] and arr[j]
+	                
+	                int temp = arr[count];
+	                arr[count] = arr[j];
+	                arr[j] = temp;
+	            }
+	        }
+	        
+	        //swap arr[i+1] and pivot
+	        
+	        int temp = arr[count+1];
+	        arr[count+1] = arr[high];
+	        arr[high] = temp;
+	        
+	        return count+1;
+	    }
+	    
+	    
+	    public static void sort(int[] arr, int low, int high){
+	        if (low<high){
+	            int pivot = partition(arr, low, high);
+	            sort(arr, low, pivot-1);
+	            sort(arr, pivot+1, high);
+	        }
+	    }
+		
+		public static void quickSort(int[] input) {
+			/* Your class should be named Solution
+			 * Don't write main().
+			 * Don't read input, it is passed as function argument.
+			 * No need to print or return the output.
+			 * Taking input and printing output is handled automatically.
+			 */
+	        int start = 0;
+	        int end = input.length-1;
+	        sort(input, start, end);
+			
+		}
+		
+
+}