Remove k digits
class Solution: def removeKdigits(self, num: str, k: int) -> str: if len(num) == k:#no need to search, just return 0 return str(0) point = 0 #use the point to traverse the num while(k>0 and point < len(num)-1): if num[point] > num[point+1]: #from left to right, each time we check if the digit that is larger than the digit behind num = num[:point]+num[point+1:] #if so, delete that digit k-=1 if point!=0:#except point equals to 0, we step back one digit point-=1 continue #jump the point+=1 statement point+=1 if k == 0:#num[:-k] is not valid if k==0 return str(i...