119 lines
2.8 KiB
Python
119 lines
2.8 KiB
Python
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#!/usr/bin/env python3
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class State:
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left_cats = 0
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left_dogs = 0
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right_cats = 0
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right_dogs = 0
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boat_side = "left"
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actions = []
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def __init__(self, lc, ld, side):
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self.left_cats = lc
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self.left_dogs = ld
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self.right_cats = 3 - lc
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self.right_dogs = 3 - ld
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self.boat_side = side
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def row(self, direction, cats, dogs):
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for act in self.actions:
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if (act.direction == direction and act.required_cats == cats
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and act.required_dogs == dogs):
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return act.result_state
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def add_action(self, act):
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self.actions.append(act)
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class Action:
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required_cats = 0
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required_dogs = 0
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direction = "left"
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result_state = None
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def __init__(self, source, dest):
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self.required_cats = abs(source.left_cats - dest.left_cats)
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self.required_dogs = abs(source.left_dogs - dest.left_dogs)
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self.boat_side = "left"
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if source.boat_side == "left":
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self.boat_side = "right"
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self.result_state = dest
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source.add_action(self)
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start = State(3, 3, "left") # Starting point
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g31 = State(3, 1, "right")
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g22 = State(2, 2, "right")
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g31 = State(3, 2, "right")
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Action(start, g31)
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Action(start, g22)
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Action(start, g31)
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b32 = State(3, 2, "left")
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g30 = State(3, 0, "right")
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b31 = State(3, 1, "left")
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g11 = State(1, 1, "right")
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Action(g31, b32)
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Action(g22, b32)
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Action(b32, g30)
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Action(g30, b31)
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Action(b31, g11)
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g01 = State(0, 1, "right")
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b03 = State(0, 3, "left")
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g02 = State(0, 2, "right")
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b22 = State(2, 2, "left")
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Action(g11, b22)
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Action(b22, g02)
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Action(g02, b03)
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Action(b03, g01)
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b02 = State(0, 2, "left")
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b11 = State(1, 1, "left")
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b01 = State(0, 1, "left")
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Action(g01, b02)
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Action(g01, b11)
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end = State(0, 0, "right")
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Action(b02, end)
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Action(b11, end)
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Action(b01, end)
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def is_goal(state):
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return state.right_cats == 3 and state.right_dogs == 3
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def depth_limited_search(node, depth):
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if depth == 0:
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if is_goal(node):
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return (node, True)
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return (None, True)
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elif depth > 0:
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any_remaining = False
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for act in node.actions:
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child = act.result_state
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found, remaining = depth_limited_search(child, depth - 1)
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if found is not None:
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return (found, True)
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if remaining:
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any_remaining = True
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return (None, any_remaining)
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def iterative_deepening_dfs(root):
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for depth in range(0, 999):
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found, remaining = depth_limited_search(root, depth)
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if found is not None:
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return found
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elif not remaining:
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return None
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print("Overflow in iterative deepening depth-first search")
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finish = iterative_deepening_dfs(start)
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if finish:
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print("Finished DFS of path")
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