打印给定元素的排列和组合的程序

def permute(elements, prefix=[]):
    if len(elements) == 0:
        print(prefix)
    else:
        for i in range(len(elements)):
            new_prefix = prefix + [elements[i]]
            new_elements = elements[:i] + elements[i+1:]
            permute(new_elements, new_prefix)

def combine(elements, k, prefix=[]):
    if k == 0:
        print(prefix)
    else:
        for i in range(len(elements)):
            new_prefix = prefix + [elements[i]]
            new_elements = elements[i+1:]
            combine(new_elements, k-1, new_prefix)

# 示例用法
elements = ['A', 'B', 'C']
print("排列：")
permute(elements)
print("组合：")
for k in range(1, len(elements)+1):
    combine(elements, k)