from Imports import*

def breadth_first_search(problem):
    "Search shallowest nodes in the search tree first."
    node = Node(problem.initial)
    if problem.is_goal(problem.initial):
        return node
    frontier = FIFOQueue([node])
    reached = {problem.initial}
    while frontier:
        node = frontier.pop()
        for child in expand(problem, node):
            s = child.state
            if problem.is_goal(s):
                return child
            if s not in reached:
                reached.add(s)
                frontier.appendleft(child)
    return failure


def iterative_deepening_search(problem):
    "Do depth-limited search with increasing depth limits."
    for limit in range(1, sys.maxsize):
        result = depth_limited_search(problem, limit)
        if result != cutoff:
            return result
        
        
def depth_limited_search(problem, limit=10):
    "Search deepest nodes in the search tree first."
    frontier = LIFOQueue([Node(problem.initial)])
    result = failure
    while frontier:
        node = frontier.pop()
        if problem.is_goal(node.state):
            return node
        elif len(node) >= limit:
            result = cutoff
        elif not is_cycle(node):
            for child in expand(problem, node):
                frontier.append(child)
    return result


def depth_first_recursive_search(problem, node=None):
    if node is None: 
        node = Node(problem.initial)
    if problem.is_goal(node.state):
        return node
    elif is_cycle(node):
        return failure
    else:
        for child in expand(problem, node):
            result = depth_first_recursive_search(problem, child)
            if result:
                return result
        return failure

fc86021e2ea3f7448e7a4589c92ea97970eafc89
<mask token>


def breadth_first_search(problem):
    """Search shallowest nodes in the search tree first."""
    node = Node(problem.initial)
    if problem.is_goal(problem.initial):
        return node
    frontier = FIFOQueue([node])
    reached = {problem.initial}
    while frontier:
        node = frontier.pop()
        for child in expand(problem, node):
            s = child.state
            if problem.is_goal(s):
                return child
            if s not in reached:
                reached.add(s)
                frontier.appendleft(child)
    return failure


<mask token>

<mask token>


def breadth_first_search(problem):
    """Search shallowest nodes in the search tree first."""
    node = Node(problem.initial)
    if problem.is_goal(problem.initial):
        return node
    frontier = FIFOQueue([node])
    reached = {problem.initial}
    while frontier:
        node = frontier.pop()
        for child in expand(problem, node):
            s = child.state
            if problem.is_goal(s):
                return child
            if s not in reached:
                reached.add(s)
                frontier.appendleft(child)
    return failure


def iterative_deepening_search(problem):
    """Do depth-limited search with increasing depth limits."""
    for limit in range(1, sys.maxsize):
        result = depth_limited_search(problem, limit)
        if result != cutoff:
            return result


def depth_limited_search(problem, limit=10):
    """Search deepest nodes in the search tree first."""
    frontier = LIFOQueue([Node(problem.initial)])
    result = failure
    while frontier:
        node = frontier.pop()
        if problem.is_goal(node.state):
            return node
        elif len(node) >= limit:
            result = cutoff
        elif not is_cycle(node):
            for child in expand(problem, node):
                frontier.append(child)
    return result


<mask token>

<mask token>


def breadth_first_search(problem):
    """Search shallowest nodes in the search tree first."""
    node = Node(problem.initial)
    if problem.is_goal(problem.initial):
        return node
    frontier = FIFOQueue([node])
    reached = {problem.initial}
    while frontier:
        node = frontier.pop()
        for child in expand(problem, node):
            s = child.state
            if problem.is_goal(s):
                return child
            if s not in reached:
                reached.add(s)
                frontier.appendleft(child)
    return failure


def iterative_deepening_search(problem):
    """Do depth-limited search with increasing depth limits."""
    for limit in range(1, sys.maxsize):
        result = depth_limited_search(problem, limit)
        if result != cutoff:
            return result


def depth_limited_search(problem, limit=10):
    """Search deepest nodes in the search tree first."""
    frontier = LIFOQueue([Node(problem.initial)])
    result = failure
    while frontier:
        node = frontier.pop()
        if problem.is_goal(node.state):
            return node
        elif len(node) >= limit:
            result = cutoff
        elif not is_cycle(node):
            for child in expand(problem, node):
                frontier.append(child)
    return result


def depth_first_recursive_search(problem, node=None):
    if node is None:
        node = Node(problem.initial)
    if problem.is_goal(node.state):
        return node
    elif is_cycle(node):
        return failure
    else:
        for child in expand(problem, node):
            result = depth_first_recursive_search(problem, child)
            if result:
                return result
        return failure

from Imports import *


def breadth_first_search(problem):
    """Search shallowest nodes in the search tree first."""
    node = Node(problem.initial)
    if problem.is_goal(problem.initial):
        return node
    frontier = FIFOQueue([node])
    reached = {problem.initial}
    while frontier:
        node = frontier.pop()
        for child in expand(problem, node):
            s = child.state
            if problem.is_goal(s):
                return child
            if s not in reached:
                reached.add(s)
                frontier.appendleft(child)
    return failure


def iterative_deepening_search(problem):
    """Do depth-limited search with increasing depth limits."""
    for limit in range(1, sys.maxsize):
        result = depth_limited_search(problem, limit)
        if result != cutoff:
            return result


def depth_limited_search(problem, limit=10):
    """Search deepest nodes in the search tree first."""
    frontier = LIFOQueue([Node(problem.initial)])
    result = failure
    while frontier:
        node = frontier.pop()
        if problem.is_goal(node.state):
            return node
        elif len(node) >= limit:
            result = cutoff
        elif not is_cycle(node):
            for child in expand(problem, node):
                frontier.append(child)
    return result


def depth_first_recursive_search(problem, node=None):
    if node is None:
        node = Node(problem.initial)
    if problem.is_goal(node.state):
        return node
    elif is_cycle(node):
        return failure
    else:
        for child in expand(problem, node):
            result = depth_first_recursive_search(problem, child)
            if result:
                return result
        return failure

from Imports import*

def breadth_first_search(problem):
    "Search shallowest nodes in the search tree first."
    node = Node(problem.initial)
    if problem.is_goal(problem.initial):
        return node
    frontier = FIFOQueue([node])
    reached = {problem.initial}
    while frontier:
        node = frontier.pop()
        for child in expand(problem, node):
            s = child.state
            if problem.is_goal(s):
                return child
            if s not in reached:
                reached.add(s)
                frontier.appendleft(child)
    return failure


def iterative_deepening_search(problem):
    "Do depth-limited search with increasing depth limits."
    for limit in range(1, sys.maxsize):
        result = depth_limited_search(problem, limit)
        if result != cutoff:
            return result
        
        
def depth_limited_search(problem, limit=10):
    "Search deepest nodes in the search tree first."
    frontier = LIFOQueue([Node(problem.initial)])
    result = failure
    while frontier:
        node = frontier.pop()
        if problem.is_goal(node.state):
            return node
        elif len(node) >= limit:
            result = cutoff
        elif not is_cycle(node):
            for child in expand(problem, node):
                frontier.append(child)
    return result


def depth_first_recursive_search(problem, node=None):
    if node is None: 
        node = Node(problem.initial)
    if problem.is_goal(node.state):
        return node
    elif is_cycle(node):
        return failure
    else:
        for child in expand(problem, node):
            result = depth_first_recursive_search(problem, child)
            if result:
                return result
        return failure
