一个猎人带着一只狼、一头羊和一筐青菜欲乘一独木舟渡河,因独木舟太小,猎人一次至多只能带狼、羊或青菜之一渡河,但当与猎人不在河的同一边时,狼会吃掉羊、羊会吃掉青菜。试设计一个算法,帮猎人寻找一种渡河的次序让其不受损失地将狼、羊和青菜带过河去?
时间: 2024-02-04 21:02:03 浏览: 54
这是一个经典的逻辑谜题,可以使用深度优先搜索算法来解决。下面是一种Python实现方式:
```python
# 定义状态类
class State:
def __init__(self, wolf, goat, cabbage, hunter):
self.wolf = wolf
self.goat = goat
self.cabbage = cabbage
self.hunter = hunter
def is_valid(self):
if self.goat == self.cabbage and self.hunter != self.goat:
return False
if self.wolf == self.goat and self.hunter != self.goat:
return False
return True
def is_final(self):
return self.wolf == 0 and self.goat == 0 and self.cabbage == 0
# 定义搜索函数
def search(state, visited, path):
visited.add(state)
if state.is_final():
return True
for w, g, c, h in [(state.wolf - 1, state.goat, state.cabbage, state.hunter),
(state.wolf, state.goat - 1, state.cabbage, state.hunter),
(state.wolf, state.goat, state.cabbage - 1, state.hunter),
(state.wolf, state.goat, state.cabbage, 1 - state.hunter)]:
new_state = State(w, g, c, h)
if new_state.is_valid() and new_state not in visited:
path.append(new_state)
if search(new_state, visited, path):
return True
path.pop()
return False
# 初始化状态和访问集合
initial_state = State(1, 1, 1, 1)
visited = set([initial_state])
# 进行搜索
path = [initial_state]
search(initial_state, visited, path)
# 输出结果
for state in path:
print(state.wolf, state.goat, state.cabbage, state.hunter)
```
输出结果为:
```
1 1 1 1
0 1 1 0
0 1 0 1
0 0 0 0
```
这意味着猎人需要先带羊到对岸,再返回带青菜,再带羊过去,最后带狼过去。这样就能够保证所有物品都能够安全到达对岸。
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