quicksort.py

Python/quicksort.py

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+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 len(arr) == 1:
+        return arr
+    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]),