Buggy python submission (verdict: Time Limit Exceeded):
import sys

class binarySearchTree:
    def __init__(self):
        self.root = None

    def insert(self, key):
        z = Node(key)
        y = None
        x = self.root
        while x:
            y = x
            if z.key < x.key:
                x = x.left
            else:
                x = x.right

        if y is None:
            self.root = z
        elif z.key < y.key:
            y.left = z
        else:
            y.right = z

    def printBT(self):
        print self.root.inorderTreeWalk()
        print self.root.preorderTreeWalk()

class Node:
    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None

    def inorderTreeWalk(self):
        ret = ""
        if self.left:
            ret += self.left.inorderTreeWalk()
        ret += " " + str(self.key)
        if self.right:
            ret += self.right.inorderTreeWalk()

        return ret

    def preorderTreeWalk(self):
        ret = " " + str(self.key)
        if self.left:
            ret += self.left.preorderTreeWalk()
        if self.right:
            ret += self.right.preorderTreeWalk()

        return ret

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    bt = binarySearchTree()
    for line in lines:
        if line[0] == "i":
            bt.insert(int(line[6:]))
        else:
            bt.printBT()

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Runtime Error):
import sys

class binarySearchTree:
    def __init__(self):
        self.root = None

    def insert(self, key):
        z = Node(key)
        y = None
        x = self.root
        while x:
            y = x
            if z.key < x.key:
                x = x.left
            else:
                x = x.right

        if y is None:
            self.root = z
        elif z.key < y.key:
            y.left = z
        else:
            y.right = z

    def printBT(self):
        print self.root.inorderTreeWalk()
        print self.root.preorderTreeWalk()

class Node:
    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None

    def inorderTreeWalk(self):
        ret = ""
        if self.left:
            ret += self.left.inorderTreeWalk()
        ret += " " + str(self.key)
        if self.right:
            ret += self.right.inorderTreeWalk()

        return ret

    def preorderTreeWalk(self):
        ret = " " + str(self.key)
        if self.left:
            ret += self.left.preorderTreeWalk()
        if self.right:
            ret += self.right.preorderTreeWalk()

        return ret

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    bt = binarySearchTree()
    for line in lines:
        if line[0] == "i":
            bt.insert(int(line.split()[1])
        else:
            bt.printBT()

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Time Limit Exceeded):
import sys

class binarySearchTree:
    def __init__(self):
        self.root = None

    def insert(self, key):
        z = Node(key)
        y = None
        x = self.root
        while x:
            y = x
            if z.key < x.key:
                x = x.left
            else:
                x = x.right

        if y is None:
            self.root = z
        elif z.key < y.key:
            y.left = z
        else:
            y.right = z

    def printBT(self):
        print self.root.inorderTreeWalk()
        print self.root.preorderTreeWalk()

class Node:
    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None

    def inorderTreeWalk(self):
        ret = ""
        if self.left:
            ret += self.left.inorderTreeWalk()
        ret += " " + str(self.key)
        if self.right:
            ret += self.right.inorderTreeWalk()

        return ret

    def preorderTreeWalk(self):
        ret = " " + str(self.key)
        if self.left:
            ret += self.left.preorderTreeWalk()
        if self.right:
            ret += self.right.preorderTreeWalk()

        return ret

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    bt = binarySearchTree()
    for line in lines:
        if line[0] == "i":
            t = line.split()
            bt.insert(int(t[1]))
        else:
            bt.printBT()

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Time Limit Exceeded):
import sys

class binarySearchTree:
    def __init__(self):
        self.root = None

    def insert(self, key):
        z = Node(key)
        y = None
        x = self.root
        while x:
            y = x
            if z.key < x.key:
                x = x.left
            else:
                x = x.right

        if y is None:
            self.root = z
        elif z.key < y.key:
            y.left = z
        else:
            y.right = z

    def printBT(self):
        print self.root.inorderTreeWalk()
        print self.root.preorderTreeWalk()

class Node:
    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None

    def inorderTreeWalk(self):
        ret = ""
        if self.left:
            ret += self.left.inorderTreeWalk()
        ret += " " + str(self.key)
        if self.right:
            ret += self.right.inorderTreeWalk()

        return ret

    def preorderTreeWalk(self):
        ret = " " + str(self.key)
        if self.left:
            ret += self.left.preorderTreeWalk()
        if self.right:
            ret += self.right.preorderTreeWalk()

        return ret

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    bt = binarySearchTree()
    for line in lines:
        if line[0] == "i":
            bt.insert(int(line.split()[1]))
        else:
            bt.printBT()

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Time Limit Exceeded):
import sys

class binarySearchTree:
    def __init__(self):
        self.root = None

    def insert(self, key):
        z = Node(key)
        y = None
        x = self.root
        while x:
            y = x
            if z.key < x.key:
                x = x.left
            else:
                x = x.right

        if y is None:
            self.root = z
        elif z.key < y.key:
            y.left = z
        else:
            y.right = z

    def printBT(self):
        print inorderTreeWalk(self.root)
        print preorderTreeWalk(self.root)

class Node:
    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None

def inorderTreeWalk(node):
    if node:
        return inorderTreeWalk(node.left) + " " + str(node.key) + inorderTreeWalk(node.right)
    return ""

def preorderTreeWalk(node):
    if node:
        return " " + str(node.key) + preorderTreeWalk(node.left) + preorderTreeWalk(node.right)
    return ""

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    bt = binarySearchTree()
    for line in lines:
        if line[0] == "i":
            bt.insert(int(line.split()[1]))
        else:
            bt.printBT()

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Time Limit Exceeded):
import sys

class binarySearchTree:
    def __init__(self):
        self.root = None

    def insert(self, key):
        z = Node(key)
        y = None
        x = self.root
        while x:
            y = x
            if z.key < x.key:
                x = x.left
            else:
                x = x.right

        if y is None:
            self.root = z
        elif z.key < y.key:
            y.left = z
        else:
            y.right = z

    def printBT(self):
        print inorderTreeWalk(self.root)
        print preorderTreeWalk(self.root)

class Node:
    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None

def inorderTreeWalk(node):
    if node:
        return inorderTreeWalk(node.left) + " " + str(node.key) + inorderTreeWalk(node.right)
    return ""

def preorderTreeWalk(node):
    if node:
        return " " + str(node.key) + preorderTreeWalk(node.left) + preorderTreeWalk(node.right)
    return ""

if __name__ == "__main__":
    lines = sys.stdin.readlines()

    bt = binarySearchTree()
    for i in range(1, int(lines[0]) + 1):
        if lines[i][0] == "i":
            bt.insert(int(lines[i].split()[1]))
        else:
            bt.printBT()

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Runtime Error):
import sys

class binarySearchTree:
    def __init__(self):
        self.root = None

    def insert(self, key):
        z = Node(key)
        y = None
        x = self.root
        while x:
            y = x
            if z.key < x.key:
                x = x.left
            else:
                x = x.right

        if y is None:
            self.root = z
        elif z.key < y.key:
            y.left = z
        else:
            y.right = z

    def printBT(self):
        print inorderTreeWalk(self.root)
        print preorderTreeWalk(self.root)

class Node:
    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None

def inorderTreeWalk(node):
    if node:
        return inorderTreeWalk(node.left) + " " + str(node.key) + inorderTreeWalk(node.right)
    return ""

def preorderTreeWalk(node):
    if node:
        return " " + str(node.key) + preorderTreeWalk(node.left) + preorderTreeWalk(node.right)
    return ""

if __name__ == "__main__":
    m = int(raw_input())
    bt = binarySearchTree()
    for i in range(m):
        line = map(str, raw_input())
        if line[0] == "i":
            bt.insert(int(line[i].split()[1]))
        else:
            bt.printBT()

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Time Limit Exceeded):
import sys

class binarySearchTree:
    def __init__(self):
        self.root = None

    def insert(self, key):
        z = Node(key)
        y = None
        x = self.root
        while x:
            y = x
            if z.key < x.key:
                x = x.left
            else:
                x = x.right

        if y is None:
            self.root = z
        elif z.key < y.key:
            y.left = z
        else:
            y.right = z

    def printBT(self):
        print inorderTreeWalk(self.root)
        print preorderTreeWalk(self.root)

class Node:
    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None

def inorderTreeWalk(node):
    if node:
        return inorderTreeWalk(node.left) + " " + str(node.key) + inorderTreeWalk(node.right)
    return ""

def preorderTreeWalk(node):
    if node:
        return " " + str(node.key) + preorderTreeWalk(node.left) + preorderTreeWalk(node.right)
    return ""

if __name__ == "__main__":
    m = int(raw_input())
    bt = binarySearchTree()
    for i in range(m):
        line = raw_input()
        if line[0] == "i":
            bt.insert(int(line.split()[1]))
        else:
            bt.printBT()

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Runtime Error):
import sys
import time

class Node:
    def __init__(self, key = None):
        self.key = key
        self.left = None
        self.right = None

def insert(key):
    global root
    z = Node(key)
    y = None
    x = root
    while x:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right

    if y is None:
        root.key = key
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    if node:
        return inorderTreeWalk(node.left) + " " + str(node.key) + inorderTreeWalk(node.right)
    return ""

def preorderTreeWalk(node):
    if node:
        return " " + str(node.key) + preorderTreeWalk(node.left) + preorderTreeWalk(node.right)
    return ""

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(int(line.split()[1]))
        else:
            print inorderTreeWalk(root)
            print preorderTreeWalk(root)

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Time Limit Exceeded):
import sys
import time

class Node:
    def __init__(self, key = None):
        self.key = key
        self.left = None
        self.right = None

def insert(key):
    global root
    z = Node(key)
    y = None
    x = root
    while x:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right

    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    if node:
        return inorderTreeWalk(node.left) + " " + str(node.key) + inorderTreeWalk(node.right)
    return ""

def preorderTreeWalk(node):
    if node:
        return " " + str(node.key) + preorderTreeWalk(node.left) + preorderTreeWalk(node.right)
    return ""

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(int(line.split()[1]))
        else:
            print inorderTreeWalk(root)
            print preorderTreeWalk(root)

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Time Limit Exceeded):
import sys
import time

class Node:
    def __init__(self, key = None):
        self.key = key
        self.left = None
        self.right = None

def insert(key):
    global root
    z = Node(key)
    y = None
    x = root
    while x:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right

    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(int(line.split()[1]))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Runtime Error):
import sys
import time

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(key, z):
    global root
    y = None
    x = root
    while x:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Buggy python submission (verdict: Time Limit Exceeded):
import sys
import time

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))

Fixed submission:
import sys

class Node:
    def __init__(self, key):
        self.key = key
        self.parent = None
        self.left = None
        self.right = None

def insert(z):
    global root
    y = None
    x = root
    while x is not None:
        y = x
        if z.key < x.key:
            x = x.left
        else:
            x = x.right
    z.parent = y
    if y is None:
        root = z
    elif z.key < y.key:
        y.left = z
    else:
        y.right = z

def inorderTreeWalk(node):
    global In
    if node:
        inorderTreeWalk(node.left)
        In.append(str(node.key))
        inorderTreeWalk(node.right)

def preorderTreeWalk(node):
    global Pre
    if node:
        Pre.append(str(node.key))
        preorderTreeWalk(node.left)
        preorderTreeWalk(node.right)

if __name__ == "__main__":
    lines = sys.stdin.readlines()
    del lines[0]

    root = None
    for line in lines:
        if line[0] == "i":
            insert(Node(int(line.split()[1])))
        else:
            In = []
            Pre = []
            inorderTreeWalk(root)
            print " " + " ".join(map(str, In))
            preorderTreeWalk(root)
            print " " + " ".join(map(str, Pre))