class Solution:
    def removeKdigits(self, num: str, k: int) -> str:
        digits = []
        for d in num:
            if not digits and d == "0":
                continue

            if d == "0" and k >= len(digits):
                k -= len(digits)
                digits = []
                continue

            while digits and k > 0 and d < digits[-1]:
                digits.pop()
                k -= 1
            digits.append(d)

        while k > 0 and digits:
            k -= 1
            digits.pop()

        if not digits:
            return "0"
        return "".join(digits)