如何将此递归更改为尾部递归？

Question

下面是递归代码，我正试图将其改为尾部递归

def stairClimb(n):
    if n <= 3:
        WaysToClimb = [1, 2, 4]
        return WaysToClimb[n - 1]
    else:
        return stairClimb(n - 1) + stairClimb(n - 2) + stairClimb(n - 3)

Answer 1

使用累加器：

def stairClimb(n, acc, acc1, acc2):

if n == 3:
    return acc2
else:
    return stairClimb(n-1, acc1, acc2, acc+acc1+acc2)

用开头的数字来称呼它：

stairClimb(n, 1, 2, 4)