题目:
题解:
class Solution:def removeKdigits(self, num: str, k: int) -> str:numStack = []# 构建单调递增的数字串for digit in num:while k and numStack and numStack[-1] > digit:numStack.pop()k -= 1numStack.append(digit)# 如果 K > 0,删除末尾的 K 个字符finalStack = numStack[:-k] if k else numStack# 抹去前导零return "".join(finalStack).lstrip('0') or "0"