求O(n)中一个字符串的所有循环排列

def generate_permutations(s, chosen, available, result):
    if not available:
        result.append(chosen)
        return
    
    for i in range(len(available)):
        ch = available[i]
        chosen += ch
        available = available[:i] + available[i+1:]
        
        generate_permutations(s, chosen, available, result)
        
        chosen = chosen[:-1]
        available = available[:i] + ch + available[i:]
        
def get_all_permutations(s):
    result = []
    generate_permutations(s, "", s, result)
    return result

# 测试示例
string = "abc"
permutations = get_all_permutations(string)
print(permutations)