VI Zadaci za vezbanje prv kolokvium - Sudoku

import bisect

"""
Defining a class for the problem structure that we will solve with a search.
The Problem class is an abstract class from which we make inheritance to define the basic
characteristics of every problem we want to solve
"""


class Problem:
    def __init__(self, initial, goal=None):
        self.initial = initial
        self.goal = goal

    def successor(self, state):
        """Given a state, return a dictionary of {action : state} pairs reachable
        from this state. If there are many successors, consider an iterator
        that yields the successors one at a time, rather than building them
        all at once.

        :param state: given state
        :return:  dictionary of {action : state} pairs reachable
                  from this state
        :rtype: dict
        """
        raise NotImplementedError

    def actions(self, state):
        """Given a state, return a list of all actions possible
        from that state

        :param state: given state
        :return: list of actions
        :rtype: list
        """
        raise NotImplementedError

    def result(self, state, action):
        """Given a state and action, return the resulting state

        :param state: given state
        :param action: given action
        :return: resulting state
        """
        raise NotImplementedError

    def goal_test(self, state):
        """Return True if the state is a goal. The default method compares
        the state to self.goal, as specified in the constructor. Implement
        this method if checking against a single self.goal is not enough.

        :param state: given state
        :return: is the given state a goal state
        :rtype: bool
        """
        return state == self.goal

    def path_cost(self, c, state1, action, state2):
        """Return the cost of a solution path that arrives at state2 from state1
        via action, assuming cost c to get up to state1. If the problem is such
        that the path doesn't matter, this function will only look at state2.
        If the path does matter, it will consider c and maybe state1 and action.
        The default method costs 1 for every step in the path.

        :param c: cost of the path to get up to state1
        :param state1: given current state
        :param action: action that needs to be done
        :param state2: state to arrive to
        :return: cost of the path after executing the action
        :rtype: float
        """
        return c + 1

    def value(self):
        """For optimization problems, each state has a value.
        Hill-climbing and related algorithms try to maximize this value.

        :return: state value
        :rtype: float
        """
        raise NotImplementedError


"""
Definition of the class for node structure of the search.
The class Node is not inherited
"""


class Node:
    def __init__(self, state, parent=None, action=None, path_cost=0):
        """Create node from the search tree,  obtained from the parent by
        taking the action

        :param state: current state
        :param parent: parent state
        :param action: action
        :param path_cost: path cost
        """
        self.state = state
        self.parent = parent
        self.action = action
        self.path_cost = path_cost
        self.depth = 0  # search depth
        if parent:
            self.depth = parent.depth + 1

    def __repr__(self):
        return "<Node %s>" % (self.state,)

    def __lt__(self, node):
        return self.state < node.state

    def expand(self, problem):
        """List the nodes reachable in one step from this node.

        :param problem: given problem
        :return: list of available nodes in one step
        :rtype: list(Node)
        """
        return [self.child_node(problem, action)
                for action in problem.actions(self.state)]

    def child_node(self, problem, action):
        """Return a child node from this node

        :param problem: given problem
        :param action: given action
        :return: available node  according to the given action
        :rtype: Node
        """
        next_state = problem.result(self.state, action)
        return Node(next_state, self, action,
                    problem.path_cost(self.path_cost, self.state,
                                      action, next_state))

    def solution(self):
        """Return the sequence of actions to go from the root to this node.

        :return: sequence of actions
        :rtype: list
        """
        return [node.action for node in self.path()[1:]]

    def solve(self):
        """Return the sequence of states to go from the root to this node.

        :return: list of states
        :rtype: list
        """
        return [node.state for node in self.path()[0:]]

    def path(self):
        """Return a list of nodes forming the path from the root to this node.

        :return: list of states from the path
        :rtype: list(Node)
        """
        x, result = self, []
        while x:
            result.append(x)
            x = x.parent
        result.reverse()
        return result

    """We want the queue of nodes at breadth_first_search or
    astar_search to not contain states-duplicates, so the nodes that
    contain the same condition we treat as the same. [Problem: this can
    not be desirable in other situations.]"""

    def __eq__(self, other):
        return isinstance(other, Node) and self.state == other.state

    def __hash__(self):
        return hash(self.state)


"""
Definitions of helper structures for storing the list of generated, but not checked nodes
"""


class Queue:
    """Queue is an abstract class/interface. There are three types:
        Stack(): Last In First Out Queue (stack).
        FIFOQueue(): First In First Out Queue.
        PriorityQueue(order, f): Queue in sorted order (default min-first).
    """

    def __init__(self):
        raise NotImplementedError

    def append(self, item):
        """Adds the item into the queue

        :param item: given element
        :return: None
        """
        raise NotImplementedError

    def extend(self, items):
        """Adds the items into the queue

        :param items: given elements
        :return: None
        """
        raise NotImplementedError

    def pop(self):
        """Returns the first element of the queue

        :return: first element
        """
        raise NotImplementedError

    def __len__(self):
        """Returns the number of elements in the queue

        :return: number of elements in the queue
        :rtype: int
        """
        raise NotImplementedError

    def __contains__(self, item):
        """Check if the queue contains the element item

        :param item: given element
        :return: whether the queue contains the item
        :rtype: bool
        """
        raise NotImplementedError


class Stack(Queue):
    """Last-In-First-Out Queue."""

    def __init__(self):
        self.data = []

    def append(self, item):
        self.data.append(item)

    def extend(self, items):
        self.data.extend(items)

    def pop(self):
        return self.data.pop()

    def __len__(self):
        return len(self.data)

    def __contains__(self, item):
        return item in self.data


class FIFOQueue(Queue):
    """First-In-First-Out Queue."""

    def __init__(self):
        self.data = []

    def append(self, item):
        self.data.append(item)

    def extend(self, items):
        self.data.extend(items)

    def pop(self):
        return self.data.pop(0)

    def __len__(self):
        return len(self.data)

    def __contains__(self, item):
        return item in self.data


class PriorityQueue(Queue):
    """A queue in which the minimum (or maximum) element is returned first
     (as determined by f and order). This structure is used in
     informed search"""

    def __init__(self, order=min, f=lambda x: x):
        """
        :param order: sorting function, if order is min, returns the element
                      with minimal f (x); if the order is max, then returns the
                      element with maximum f (x).
        :param f: function f(x)
        """
        assert order in [min, max]
        self.data = []
        self.order = order
        self.f = f

    def append(self, item):
        bisect.insort_right(self.data, (self.f(item), item))

    def extend(self, items):
        for item in items:
            bisect.insort_right(self.data, (self.f(item), item))

    def pop(self):
        if self.order == min:
            return self.data.pop(0)[1]
        return self.data.pop()[1]

    def __len__(self):
        return len(self.data)

    def __contains__(self, item):
        return any(item == pair[1] for pair in self.data)

    def __getitem__(self, key):
        for _, item in self.data:
            if item == key:
                return item

    def __delitem__(self, key):
        for i, (value, item) in enumerate(self.data):
            if item == key:
                self.data.pop(i)


"""
Uninformed graph search
The main difference is that here we do not allow loops,
i.e. repetition of states
"""


def graph_search(problem, fringe):
    """Search through the successors of a problem to find a goal.
     If two paths reach a state, only use the best one.

    :param problem: given problem
    :param fringe: empty queue
    :return: Node
    """
    closed = {}
    fringe.append(Node(problem.initial))
    while fringe:
        node = fringe.pop()
        if problem.goal_test(node.state):
            return node
        if node.state not in closed:
            closed[node.state] = True
            fringe.extend(node.expand(problem))
    return None


def breadth_first_graph_search(problem):
    """Search the shallowest nodes in the search tree first.

    :param problem: given problem
    :return: Node
    """
    return graph_search(problem, FIFOQueue())


"""
Информирано пребарување во рамки на граф
"""


def memoize(fn, slot=None):
    """ Запамети ја пресметаната вредност за која била листа од
    аргументи. Ако е специфициран slot, зачувај го резултатот во
    тој slot на првиот аргумент. Ако slot е None, зачувај ги
    резултатите во речник.

    :param fn: зададена функција
    :type fn: function
    :param slot: име на атрибут во кој се чуваат резултатите од функцијата
    :type slot: str
    :return: функција со модификација за зачувување на резултатите
    :rtype: function
    """
    if slot:
        def memoized_fn(obj, *args):
            if hasattr(obj, slot):
                return getattr(obj, slot)
            else:
                val = fn(obj, *args)
                setattr(obj, slot, val)
                return val
    else:
        def memoized_fn(*args):
            if args not in memoized_fn.cache:
                memoized_fn.cache[args] = fn(*args)
            return memoized_fn.cache[args]

        memoized_fn.cache = {}
    return memoized_fn


def best_first_graph_search(problem, f):
    """Пребарувај низ следбениците на даден проблем за да најдеш цел. Користи
     функција за евалуација за да се одлучи кој е сосед најмногу ветува и
     потоа да се истражи. Ако до дадена состојба стигнат два пата, употреби
     го најдобриот пат.

    :param problem: даден проблем
    :type problem: Problem
    :param f: дадена функција за евалуација (проценка)
    :type f: function
    :return: Node or None
    :rtype: Node
    """
    f = memoize(f, 'f')
    node = Node(problem.initial)
    if problem.goal_test(node.state):
        return node
    frontier = PriorityQueue(min, f)
    frontier.append(node)
    explored = set()
    while frontier:
        node = frontier.pop()
        if problem.goal_test(node.state):
            return node
        explored.add(node.state)
        for child in node.expand(problem):
            if child.state not in explored and child not in frontier:
                frontier.append(child)
            elif child in frontier:
                incumbent = frontier[child]
                if f(child) < f(incumbent):
                    del frontier[incumbent]
                    frontier.append(child)
    return None


def greedy_best_first_graph_search(problem, h=None):
    """ Greedy best-first пребарување се остварува ако се специфицира дека f(n) = h(n).

    :param problem: даден проблем
    :type problem: Problem
    :param h: дадена функција за хевристика
    :type h: function
    :return: Node or None
    """
    h = memoize(h or problem.h, 'h')
    return best_first_graph_search(problem, h)


def astar_search(problem, h=None):
    """ A* пребарување е best-first graph пребарување каде f(n) = g(n) + h(n).

    :param problem: даден проблем
    :type problem: Problem
    :param h: дадена функција за хевристика
    :type h: function
    :return: Node or None
    """
    h = memoize(h or problem.h, 'h')
    return best_first_graph_search(problem, lambda n: n.path_cost + h(n))

def manhattan(x1, y1, x2, y2):
    return abs(x1 - x2) + abs(y1 - y2)

class Squares(Problem):
    def __init__(self, initial, goal):
        super().__init__(initial, goal)

    def h(self, node):
        state = node.state
        value = 0
        one = state[0]
        one_x = one[0]
        one_y = one[1]
        value += manhattan(one_x, one_y, 0, 4)

        two = state[1]
        two_x = two[0]
        two_y = two[1]
        value += manhattan(two_x, two_y, 1, 3)

        tri = state[2]
        tri_x = tri[0]
        tri_y = tri[1]
        value += manhattan(tri_x, tri_y, 2, 2)

        four = state[3]
        four_x = four[0]
        four_y = four[1]
        value += manhattan(four_x, four_y, 3, 1)

        five = state[4]
        five_x = five[0]
        five_y = five[1]
        value += manhattan(five_x, five_y, 4, 0)

        return value

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