传教士和野人过河问题python代码编写

传教士和野人过河问题是一个经典的逻辑问题，要求将三个传教士和三个野人安全地通过一条小船过河，但是有一些限制条件需要满足：
1. 在任何一边，如果野人的数量多于传教士的数量，传教士会被野人吃掉。
2. 小船最多只能搭载两个人。
3. 在任何一边，传教士和野人的数量都不能为负数。

下面是一个用Python编写的解决传教士和野人过河问题的代码：

def is_valid_state(state):
    # 检查当前状态是否合法
    missionaries = state[0]
    cannibals = state[1]
    if missionaries < 0 or cannibals < 0 or (missionaries > 0 and cannibals > missionaries) or (missionaries < 3 and cannibals < missionaries):
        return False
    return True

def generate_next_states(state):
    # 生成下一个可能的状态
    next_states = []
    boat = state[2]
    for i in range(3):
        for j in range(3):
            if i + j > 2:
                continue
            if boat == 1:
                new_state = (state[0] - i, state[1] - j, 0)
            else:
                new_state = (state[0] + i, state[1] + j, 1)
            if is_valid_state(new_state):
                next_states.append(new_state)
    next_states

def is_goal_state(state):
    # 判断是否达到标状态
    return state == (0, 0, 0)

def solve_missionaries_and_cannibals(initial_state):
    # 使用广度优先搜索解决问题
    queue = [(initial_state, [])]
    visited = set()
    while queue:
        state, path = queue.pop(0)
        if is_goal_state(state):
            return path
        if state in visited:
            continue
        visited.add(state)
        next_states = generate_next_states(state)
        for next_state in next_states:
            queue.append((next_state, path + [next_state]))
    return None

# 测试代码
initial_state = (3, 3, 1)
path = solve_missionaries_and_cannibals(initial_state)
if path:
    print("找到解决方案：")
    for state in path:
        print(state)
else:
    print("无法找到解决方案。")