python - 使用递归分解数量

Question

给定数组

bills = [500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, 0.2, 0.1, 0.05, 0.02, 0.01]。

要求编写一个函数 decompose() 来分解数组中包含的账单金额。

---

例如 decompose(423) 将返回一个包含以下元素的列表

[200, 200, 20, 1, 1, 1]

这是我的代码:

bills = [500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, 0.2, 0.1, 0.05, 0.02, 0.01]

def decompose(amount, lst = []):
    if len(bills) == 1:
        return lst

    if amount > bills[0]:
        lst += [bills[0]]
        amount = amount - bills[0]
        return decompose(bills, lst + [bills[0]])
    return decompose(bills[1:], lst + [bills[0]]) 

print(decompose(523)) 

我的输出是:

Traceback (most recent call last):
  File "test.py", line 94, in <module>
    print(decompose(523)) 
  File "test.py", line 91, in decompose
    return decompose(bills, lst + [bills[0]])
  File "test.py", line 88, in decompose
    if amount > bills[0]:
TypeError: '>' not supported between instances of 'list' and 'int'

我该如何分解我的金额？

Answer 1

当顶部账单符合金额时，您应该递归地从金额中扣除账单值(value)，或者在保持相同金额的情况下递归移动到下一张账单:

def decompose(amount, bills):
    if not bills:
        return []
    if amount >= bills[0]:
        return [bills[0]] + decompose(amount - bills[0], bills)
    else:
        return decompose(amount, bills[1:])

这样:

bills = [500, 200, 100, 50, 20, 10, 5, 2, 1, 0.5, 0.2, 0.1, 0.05, 0.02, 0.01]
decompose(423, bills)

返回:

[200, 200, 20, 2, 1]