import numpy as np

inf = float('inf')

distances = np.array([
    [inf, 72, inf, inf, 81, 67],
    [72, inf, 26, inf, 61, inf],
    [inf, 26, inf, 53, 97, inf],
    [inf, inf, 53, inf, inf, inf],
    [81, 61, 97, inf, inf, 38],
    [67, inf, inf, inf, 38, inf]
])

def find_cycles(start, distances):
    n = len(distances)
    path = [start]
    cycles = []

    def is_valid(node, position):
        if distances[path[position - 1]][node] == inf:
            return False
        if node in path:
            return False
        return True

    def find_paths(node):
        for next_node in range(n):
            if is_valid(next_node, len(path)):
                path.append(next_node)
                if len(path) < n:
                    find_paths(next_node)
                elif len(path) == n and distances[path[-1]][start] != inf:
                    cycles.append(path.copy())
                path.pop()

    find_paths(start)
    return cycles

all_cycles = find_cycles(0, distances)

if all_cycles:
    print("经过全部节点能返回起点的回路的全部路径为：")
    for cycle in all_cycles:
        print(cycle + [cycle[0]])  # 添加起点以形成完整的回路
else:
    print("不存在经过全部节点能返回起点的回路")