Merge pull request narayancseian#56 from Kishun21/main

Create Recursive solution to sort a stack.py

Stack/Recursive solution to sort a stack.py

@@ -0,0 +1,51 @@
+from collections import deque
+
+
+# Insert the given key into the sorted stack while maintaining its sorted order.
+# This is similar to the recursive insertion sort routine
+def sortedInsert(stack, key):
+
+    # base case: if the stack is empty or
+    # the key is greater than all elements in the stack
+    if not stack or key > stack[-1]:
+        stack.append(key)
+        return
+
+    ''' We reach here when the key is smaller than the top element '''
+
+    # remove the top element
+    top = stack.pop()
+
+    # recur for the remaining elements in the stack
+    sortedInsert(stack, key)
+
+    # insert the popped element back into the stack
+    stack.append(top)
+
+
+# Recursive method to sort a stack
+def sortStack(stack):
+
+    # base case: stack is empty
+    if not stack:
+        return
+
+    # remove the top element
+    top = stack.pop()
+
+    # recur for the remaining elements in the stack
+    sortStack(stack)
+
+    # insert the popped element back into the sorted stack
+    sortedInsert(stack, top)
+
+
+if __name__ == '__main__':
+
+    A = [5, -2, 9, -7, 3]
+
+    stack = deque(A)
+
+    print('Stack before sorting:', list(stack))
+    sortStack(stack)
+    print('Stack after sorting:', list(stack))