Quick Sort Algorithm

Quick Sort Algorithm

Author: khanaaziz1

QuickSort.py

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+# Python program for implementation of Quicksort Sort 
+  
+# This function takes last element as pivot, places 
+# the pivot element at its correct position in sorted 
+# array, and places all smaller (smaller than pivot) 
+# to left of pivot and all greater elements to right 
+# of pivot 
+def partition(arr,low,high): 
+    i = ( low-1 )         # index of smaller element 
+    pivot = arr[high]     # pivot 
+  
+    for j in range(low , high): 
+  
+        # If current element is smaller than or 
+        # equal to pivot 
+        if   arr[j] <= pivot: 
+          
+            # increment index of smaller element 
+            i = i+1 
+            arr[i],arr[j] = arr[j],arr[i] 
+  
+    arr[i+1],arr[high] = arr[high],arr[i+1] 
+    return ( i+1 ) 
+  
+# The main function that implements QuickSort 
+# arr[] --> Array to be sorted, 
+# low  --> Starting index, 
+# high  --> Ending index 
+  
+# Function to do Quick sort 
+def quickSort(arr,low,high): 
+    if low < high: 
+  
+        # pi is partitioning index, arr[p] is now 
+        # at right place 
+        pi = partition(arr,low,high) 
+  
+        # Separately sort elements before 
+        # partition and after partition 
+        quickSort(arr, low, pi-1) 
+        quickSort(arr, pi+1, high) 
+  
+# Driver code to test above 
+arr = [10, 7, 8, 9, 1, 5] 
+n = len(arr) 
+quickSort(arr,0,n-1) 
+print ("Sorted array is:") 
+for i in range(n): 
+    print ("%d" %arr[i]), 
+  
+# This code is contributed by Abdul Aziz