分享一下第一题 ans = "" lk, rk = 0, n - 1 while lk <= rk: if lin[lk] < lin[rk]: ans += str(lin[lk]) lk += 1 elif lin[lk] > lin[rk]: ans += str(lin[rk]) rk -= 1 else: ans += str(lin[lk]) flagL = lk flagR = rk while lin[lk] == lin[rk] and lk < n and rk > 0: lk += 1 rk -= 1 if lin[lk] < lin[rk]: rk = flagR lk = flagL + 1 else: rk = flagR - 1 lk = flagL print(ans)