腎我只會用遞迴
昨天easy的遞迴出來慢成狗
今天的倒還行
幾乎不用改
什麼bit-op的我資質不夠:(
昨天的
def kthCharacter(self, k: int) -> str:
def help(k, depth):
if k==1:
return chr((ord('a')+depth%26))
else:
return help(k-2**(floor(log2(k-1))), depth+1)
return help(k,0)
今天的
def kthCharacter(self, k: int, operations: List[int]) -> str:
def help(k, depth):
if k==1:
return chr((ord('a')+depth%26))
else:
half_power = floor(log2(k-1))
op = operations[half_power]
return help((k-2**half_power), depth+op)
return help(k,0)