Merge pull request TheAlgorithms#4 from vincenzobaz/master

Add quicksort

Author: dynamitechetan

QuickSort.py

@@ -0,0 +1,29 @@
+
+def quicksort(A, p, r):
+    if p < r:
+        q = partition(A, p, r)
+        quicksort(A, p, q - 1)
+        quicksort(A, q + 1, r)
+
+
+def partition(A, p, r):
+    x = A[r]
+    i = p - 1
+    for j in range(p, r):
+        if A[j] <= x:
+            i += 1
+            tmp = A[i]
+            A[i] = A[j]
+            A[j] = tmp
+    tmp = A[i+1]
+    A[i+1] = A[r]
+    A[r] = tmp
+    return i + 1
+
+
+if __name__ == "__main__":
+    A = [8, 4, 5, 7, 1, 2, 3, 6]
+    # partition(A, 0, 7)
+    print(A)
+    quicksort(A, 0, 7)
+    print(A)