class Solution: def Typing(self , s :str): if str=='': return '' if str is None: return '' # write code here length=len(s) data=list(s) res=[] for i in range(length): if i==0 and data[i]=='<': data[0]=-1 elif data[i]=='<': for j in reversed(range(0,i)): if data[j]!=-1 and j!=-1: data[j]=-1 break data[i]=-1 # 当前字符的 实际的前面一个 字符无用 for elem in data: if elem != -1: res.append(elem) return ''.join(res)