def __init__(self, maze, mode):
"""
Inputs:
maze: a MazeClass.Maze instance
mode: one of "BFS", "DFS", or "RND"
"""
self.mz = maze #just made a new, shorter name.
self.free = {}
self.parents = {}
self.walls = {}
self.start = maze.start
self.end = maze.goal
if mode == "DFS":
self.frontier = LIFO_Queue()
elif mode == "BFS":
self.frontier = FIFO_Queue()
elif mode == "RND":
self.frontier = Random_Queue()
def __init__(self, maze, mode):
"""
Inputs:
maze: a MazeClass.Maze instance
mode: one of "BFS", "DFS", or "RND"
"""
self.mz = maze #just made a new, shorter name.
self.free = {}
self.parents = {}
self.walls = {}
self.start = maze.start
self.end = maze.goal
if mode == "DFS":
self.frontier = LIFO_Queue()
elif mode == "BFS":
self.frontier = FIFO_Queue()
elif mode == "RND":
self.frontier = Random_Queue()
class SearchAgent:
"""Core class for this assignment.
Stores a MazeClass.Maze instance and the results of searching that maze.
After a SearchAgent is initialized, the search() method should be run to
look for start-->goal paths in the maze. The display methods will then
show information about the search results."""
def __init__(self, maze, mode):
"""
Inputs:
maze: a MazeClass.Maze instance
mode: one of "BFS", "DFS", or "RND"
"""
self.mz = maze #just made a new, shorter name.
self.free = {}
self.parents = {}
self.walls = {}
self.start = maze.start
self.end = maze.goal
if mode == "DFS":
self.frontier = LIFO_Queue()
elif mode == "BFS":
self.frontier = FIFO_Queue()
elif mode == "RND":
self.frontier = Random_Queue()
def search(self):
"""Searches from start until it reaches goal or proves that it can't.
On return, all visited states will appear in self.walls or self.free,
and self.parents will reflect how each visited state was reached. The
type of queue used to store the frontier determines which states are
visited in which order.
search() takes no inputs and has no return value.
"""
#thank you for the pseudocode!
self.frontier.add(self.start)
self.parents[self.start] = None
while len(self.frontier) != 0:
self.curr = self.frontier.get()
if self.mz.is_wall(self.curr):
self.walls[self.curr] = None
else:
self.free[self.curr] = None
if self.curr == self.end:
return
for i in self.mz.neighbors(self.curr):
if i not in self.parents:
self.parents[i] = self.curr
self.frontier.add(i)
def path_to(self, state):
"""Returns a list of (row, col) pairs along a path from start-->state.
Should only be called after search(). If state has not been reached,
an empty list is returned.
"""
ret = []
if self.curr != self.end:
return ret
#follows trace from end to start, bc curr is at the end
self.trace = self.curr
while self.trace != self.start:
ret.append(self.trace)
self.trace = self.parents[self.trace]
ret.append(self.trace)
return ret
def display_path(self):
"""Prints the maze with a path from start-->goal if one was found.
Should only be called after search()."""
rep = u""
path = self.path_to(self.mz.goal)
for r in range(self.mz.rows):
for c in range(self.mz.cols):
rep += self._path_char((r, c), path) + " "
rep += "\n"
print rep
def _path_char(self, state, path):
"""Helper function for display_path()."""
if state in path:
return PATH
return self.mz._display_char(self.curr)
def display_parents(self):
"""Prints a representation of the agent's knowledge of the maze.
Should be called after search(). Visited free cells are represented by
an arrow pointing in the direction of their parent. Unvisited cells
are displayed as blanks."""
rep = u""
for r in range(self.mz.rows):
for c in range(self.mz.cols):
rep += self._parent_char((r, c)) + " "
rep += "\n"
print rep
def _parent_char(self, state):
"""Helper function for display_parents()."""
if state == self.mz.start:
return EMPTY
if state in self.walls:
return WALL
if state in self.free:
p = self.parents[state]
if p[0] < state[0]:
return UP
if p[0] > state[0]:
return DOWN
if p[1] < state[1]:
return LEFT
if p[1] > state[1]:
return RIGHT
return UNKNOWN
class SearchAgent:
"""Core class for this assignment.
Stores a MazeClass.Maze instance and the results of searching that maze.
After a SearchAgent is initialized, the search() method should be run to
look for start-->goal paths in the maze. The display methods will then
show information about the search results."""
def __init__(self, maze, mode):
"""
Inputs:
maze: a MazeClass.Maze instance
mode: one of "BFS", "DFS", or "RND"
"""
self.mz = maze #just made a new, shorter name.
self.free = {}
self.parents = {}
self.walls = {}
self.start = maze.start
self.end = maze.goal
if mode == "DFS":
self.frontier = LIFO_Queue()
elif mode == "BFS":
self.frontier = FIFO_Queue()
elif mode == "RND":
self.frontier = Random_Queue()
def search(self):
"""Searches from start until it reaches goal or proves that it can't.
On return, all visited states will appear in self.walls or self.free,
and self.parents will reflect how each visited state was reached. The
type of queue used to store the frontier determines which states are
visited in which order.
search() takes no inputs and has no return value.
"""
#thank you for the pseudocode!
self.frontier.add(self.start)
self.parents[self.start] = None
while len(self.frontier) != 0:
self.curr = self.frontier.get()
if self.mz.is_wall(self.curr):
self.walls[self.curr] = None
else:
self.free[self.curr] = None
if self.curr == self.end:
return
for i in self.mz.neighbors(self.curr):
if i not in self.parents:
self.parents[i] = self.curr
self.frontier.add(i)
def path_to(self, state):
"""Returns a list of (row, col) pairs along a path from start-->state.
Should only be called after search(). If state has not been reached,
an empty list is returned.
"""
ret = []
if self.curr != self.end:
return ret
#follows trace from end to start, bc curr is at the end
self.trace = self.curr
while self.trace!= self.start:
ret.append(self.trace)
self.trace= self.parents[self.trace]
ret.append(self.trace)
return ret
def display_path(self):
"""Prints the maze with a path from start-->goal if one was found.
Should only be called after search()."""
rep = u""
path = self.path_to(self.mz.goal)
for r in range(self.mz.rows):
for c in range(self.mz.cols):
rep += self._path_char((r,c), path) + " "
rep += "\n"
print rep
def _path_char(self, state, path):
"""Helper function for display_path()."""
if state in path:
return PATH
return self.mz._display_char(self.curr)
def display_parents(self):
"""Prints a representation of the agent's knowledge of the maze.
Should be called after search(). Visited free cells are represented by
an arrow pointing in the direction of their parent. Unvisited cells
are displayed as blanks."""
rep = u""
for r in range(self.mz.rows):
for c in range(self.mz.cols):
rep += self._parent_char((r,c)) + " "
rep += "\n"
print rep
def _parent_char(self, state):
"""Helper function for display_parents()."""
if state == self.mz.start:
return EMPTY
if state in self.walls:
return WALL
if state in self.free:
p = self.parents[state]
if p[0] < state[0]:
return UP
if p[0] > state[0]:
return DOWN
if p[1] < state[1]:
return LEFT
if p[1] > state[1]:
return RIGHT
return UNKNOWN