import re chars = input() chars = re.sub(r"([-+*/()])", r" \1 ", chars) tmp = chars.split() tokens = [] #处理负数 f = False for i, x in enumerate(tmp): if f == True: f = False continue if x == '-' and (i == 0 or tmp[i-1] == '('): tokens.append(''.join(tmp[i:i+2])) f = True else: tokens.app...