class Solution(object):

def removeKdigits(self, num, k):

"""

:type num: str

:type k: int

:rtype: str

"""

# Using Stack and Iterating

# Handle case of k being greater than the length of the array

if k >= len(num):

return "0"

# Control variable declaration

stack = []

deleted = 0

# Iteration across the num

for i in range(len(num)):

# Clear the stack if the last element inserted is greater than the current element

while len(stack) > 0 and stack[-1] > num[i] and deleted < k:

deleted += 1

stack.pop()

stack.append(num[i])

# If deleted is not equal to k, delete until k elements have been removed

while len(stack) > 0 and deleted < k:

deleted += 1

stack.pop()

return str(int("".join(stack)))

"""

# Works for all the cases -- Time Limit Exceeded

import itertools

mini = float('inf')

nums = list(num)

repeat = len(nums)-k

if repeat == 0:

return "0"

for comb in itertools.combinations(nums, r=repeat):

if int("".join(comb)) < mini:

mini = int("".join(comb))

return str(mini)

"""