Exemplo n.º 1
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 def insert(self, num):
     if len(self.right) == len(self.left):
         push(self.left, -num)
         push(self.right, -pop(self.left))
     else:
         push(self.right, num)
         push(self.left, -pop(self.right))
Exemplo n.º 2
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    def minMeetingRooms(self, intervals: List[List[int]]) -> int:

        # base case - If there is no meeting to schedule then no room needs to be allocated.
        if not intervals:
            return 0

        # The heap initialization
        free_rooms = []

        # Sort the meetings in increasing order of their start time.
        intervals.sort(key=lambda x: x[0])

        # Add the first meeting. We have to give a new room to the first meeting.
        push(free_rooms, intervals[0][1])

        # For all the remaining meeting rooms
        for i in intervals[1:]:
            # end time in heap <= start time of interval
            if free_rooms[0] <= i[0]:
                pop(free_rooms)

            # for the existing room or the new room
            push(free_rooms, i[1])

        return len(free_rooms)
Exemplo n.º 3
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def main():
    line = lambda: stdin.readline().split()
    n, k = map(int, line())

    # Patients
    patients = []
    # Accidents
    accidents = {}
    # Times
    times = []
    # Output list for fast printing
    outs = []

    # Read in input
    for _ in range(n):
        inp = line()
        if inp[0] == "1":
            _, t, name, s = inp
            patients.append(tup(int(s), int(t), name))
        elif inp[0] == "2":
            times.append(int(inp[1]))
        else:
            _, t, name = inp
            accidents[name] = int(t)

    # t values given in increasing order
    # Check the last time value to get the severity cost of EVERY patient
    # Because extra time added after the first time they can be served is equal for all patients,
    # Adding them as soon as they are available alleviates the need to update the cost later
    last_time = times[-1]
    for patient in patients:
        patient.s += (last_time - patient.t) * k

    # Use a heap to store all patients who can currently be served
    # Update the heap at each new serve-time
    q = []
    # Index for the current patient
    i = 0
    for j in range(len(times)):
        curr_time = times[j]

        # Find all patients who can now be served at this time
        while (i < len(patients) and patients[i].t <= curr_time):
            push(q, patients[i])
            i += 1

        # Find the best patient to serve, or take a break if there are none
        while (q and q[0].name in accidents
               and accidents[q[0].name] <= curr_time):
            # Remove patients who have had accidents and must leave the clinic
            pop(q)

        if q:
            best = pop(q)
            outs.append(best.name)
        else:
            outs.append("doctor takes a break")

    # Print all output at once, helps for large output sizes
    print("\n".join(outs))
def huffman(freq):
    global tree
    if len(freq) == 2:
        expand(freq[0], freq[1])
    else:
        a = pop(freq)
        b = pop(freq)
        push(freq, (a[0] + b[0], a[1] + " " + b[1]))
        huffman(freq)
        expand(a, b)
Exemplo n.º 5
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def k_largest(stream, k):
    q = []

    for elem in stream:
        if len(q) < k:
            push(q, elem)
        elif q[0] < elem:
            pop(q)
            push(q, elem)

    return q
Exemplo n.º 6
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 def findKthLargest(self, nums: List[int], k: int) -> int:
     # list to act as min heap
     hq = []
     # adding k elements to the heap
     for i in range(len(nums)):
         push(hq, nums[i])
         # if elements in heap exceed k remove the smallest
         if len(hq) > k:
             pop(hq)
     # returning the smallest element
     return hq[0]
Exemplo n.º 7
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def solution(o, i=0, sh=set(), nh=[], xh=[]):
    for e in o:
        if (v := e.split(" "))[0] == "I":
            push(nh, (int(v[1]), i))
            push(xh, (-int(v[1]), i))
            sh.add(i)
            i += 1
        elif sh:
            m = xh if v[1] == "1" else nh
            while (k := pop(m))[1] not in sh:
                pass
Exemplo n.º 8
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def connect_n_ropes(ropes):
    heap = []

    for r in ropes:
        push(heap, r)

    while len(heap) > 1:
        first = pop(heap)
        second = pop(heap)
        push(heap, first + second)

    return heap[0]
Exemplo n.º 9
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    def add(self, val):
        push(self.secondHalf, val)
        if (len(self.secondHalf) > len(self.firstHalf) + 1):
            push(self.firstHalf, -pop(self.secondHalf))

        if (len(self.firstHalf) and self.secondHalf[0] < -self.firstHalf[0]):
            push(self.firstHalf, -pop(self.secondHalf))

        if (len(self.secondHalf) + 1 < len(self.firstHalf)):
            push(self.secondHalf, -pop(self.firstHalf))

        return self.getMedian()
Exemplo n.º 10
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def medians(numbers):
    numbers = iter(numbers)
    left, right = [], []
    while True:
        #odd items
        push(left, -next(numbers))
        push(right, -pop(left))
        yield right[0]

        #even items
        push(right, next(numbers))
        push(left, -pop(right))
        yield (right[0] - left[0])/2.0
Exemplo n.º 11
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 def addNum(self, x):
     """
     :type num: int
     :rtype: None
     """
     if len(self.right) == len(self.left):
         push(self.right, x)
         _min = pop(self.right)
         push(self.left, -_min)
     else:
         push(self.left, - x )
         _max = pop(self.left)
         push(self.right, -1*_max) 
Exemplo n.º 12
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    def __init__(self, file_name):
        stat = {}
        file = open(file_name, mode='r')
        for _ch in file.read():
            # print(_ch)
            ch = _ch
            if ch in stat.keys():
                stat[ch] += 1
            else:
                stat[ch] = 1
        file.close()

        from heapq import heappush as push, heappop as pop
        forest = []
        for ch in sorted(stat.keys()):
            push(forest, Tree(True, ch, stat[ch]))

        while len(forest) >= 2:
            left = pop(forest)
            right = pop(forest)
            push(forest, Tree(left=left, right=right, weight=(left.weight + right.weight)))

        self.t = pop(forest)
        base = {}

        def rec(t, tmp):
            if t.leaf == True:
                base[t.value] = tmp
            else:
                rec(t.left, tmp + ['0'])
                rec(t.right, tmp + ['1'])
        rec(self.t, [])

        self.a = []
        buffer = []
        file = open(file_name, mode='r')
        for _ch in file.read():
            ch = _ch
            for b in base[ch]:
                if len(buffer) == 8:
                    tmp = 0
                    for i in range(8):
                        tmp *= 2
                        if buffer[i] == '1':
                            tmp += 1
                    self.a += [tmp]
                    buffer = []
                buffer += [b]
        self.tail = buffer
        file.close()
Exemplo n.º 13
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 def lastStoneWeight(self, stones: List[int]) -> int:
     stones = [-1 * x for x in stones]
     heapify(stones)
     while True:
         currLen = len(stones)
         if currLen > 1:
             mx1 = -1 * pop(stones)
             mx2 = -1 * pop(stones)
             if mx1 != mx2:
                 push(stones, -1 * abs(mx1 - mx2))
         elif currLen == 1:
             return -1 * stones[0]
         else:
             return 0
    def findKthLargest(self, nums: List[int], k: int) -> int:
        if not nums:
            return 0
        # declare min heap
        min_heap = []

        # push elements to heap and as soon as size exceeds k(remove smallest element)

        for i in range(len(nums)):
            push(min_heap, nums[i])

            if len(min_heap) > k:
                pop(min_heap)

        return min_heap[0]
Exemplo n.º 15
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    def findKthLargest(self, nums: List[int], k: int) -> int:
        # base case
        if not nums or not k or k < 0:
            return None

        # declare min heap
        min_heap = []

        # push each element to heap and as soon as heap size exceeds k, remove smallest element
        for num in nums:
            push(min_heap, num)

            if len(min_heap) > k:
                pop(min_heap)

        return min_heap[0]
Exemplo n.º 16
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def solution(operations):
    answer = list()
    for e in operations:
        a, b = e.split()
        b = int(b)
        temp = list()
        if a == "I":
            heapq.heappush(answer, b)
        elif a == "D":
            if len(answer) == 0:
                continue
            else:
                if b == 1:
                    answer.pop()
                else:
                    for _ in range(len(answer)):
                        a = heapq.pop(answer)
                        temp.append(a)
                    temp[-1]

    if len(answer) == 0:
        return [0, 0]
    else:
        anwer
        most = answer.pop()
        least = answer.popleft()
        return [most, least]
    def mergeKLists(self, lists: List[ListNode]) -> ListNode:
        if not lists or len(lists) is 0:
            return None

        # custom comparator for list node
        ListNode.__lt__ = lambda x, y: x.val < y.val

        # min heap is required to sort in ascending order
        min_heap = []

        # push only head nodes of the lists
        for head in lists:
            if head:
                push(min_heap, head)

        dummy_head = current = ListNode(-1)

        while len(min_heap) > 0:
            min_node = pop(min_heap)
            current.next = min_node

            if min_node.next:
                push(min_heap, min_node.next)

            current = current.next

        return dummy_head.next
Exemplo n.º 18
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def searchEM(board, nodesToExpand=10000):
    startNode = createFunction(board)

    heap = []
    push(heap, (-startNode.score, startNode))
    i = 0
    while i < nodesToExpand:
        start = time.time()
        if len(heap) == 0:
            break
        thisNode = pop(heap)[1]
        if not thisNode.expanded:
            thisNode.expand()
            for a in ["L", "R", "D", "U"]:
                for childNode, _ in thisNode.children[a]:
                    push(heap, (-childNode.score, childNode))
            i += 1

            # print "time to expand:" , time.time()-start

    Node.allNodes = {}

    # print (startNode.bestDir)
    # pdb.set_trace()
    startNode.downdate()
    return board.move(startNode.bestDir)
Exemplo n.º 19
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    def mergeKLists(self, lists: List[ListNode]) -> ListNode:

        #   custom less than comparator using a lambda function taking ListNode objects x and y as parameters
        lessThan = lambda x, y: x.val < y.val
        ListNode.__lt__ = lessThan

        #   initialize an empty list which acts as min heap
        minHeapK = []

        #   create a dummy head and start the cursor from that node
        dummyHead = ListNode(-1)
        cursorNode = dummyHead

        #   push into minHeap all head nodes (take care of null checks)
        for i in range(len(lists)):
            currHead = lists[i]
            if (currHead != None):
                push(minHeapK, currHead)

        #   pop min node and add it to the main linked list, and also push its next node into the min heap (if not null)
        while (len(minHeapK) > 0):

            minNode = pop(minHeapK)  #   pop the min node in the heap

            cursorNode.next = minNode
            if (minNode.next !=
                    None):  #   push to the heap only if next node exists
                push(minHeapK, minNode.next)

            cursorNode = minNode  #   update cursor node

        #   return dummy head's next node
        return dummyHead.next
Exemplo n.º 20
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    def kthSmallest(self, matrix: List[List[int]], k: int) -> int:

        #   edge case check
        if (matrix == None or len(matrix) == 0):
            return -1

        #   initializations
        nRows = len(matrix)
        nCols = len(matrix[0])
        kSmall = []

        #   first column elements inside the minHeap
        for r in range(nRows):
            currObj = ValueCell(matrix[r][0], r, 0)
            push(kSmall, currObj)

        currObj = None

        #   remove min from heap k times and insert next min element k times
        for i in range(k):
            currObj = pop(kSmall)  #   remove min element
            row = currObj.nRows  #   extract row and col of extracted min element
            col = currObj.col

            if (col + 1 <
                    nCols):  #   if next col is valid => push next col's value
                nextObj = ValueCell(matrix[row][col + 1], row, col + 1)
                push(kSmall, nextObj)

            else:  #   else min heap's size is reduced by one
                pass

        return currObj.val  #   return kth min object's value
def MST(graph):
    cost = 0
    sub_graph = {list(graph.keys())[0]: graph[list(graph.keys())[0]]}
    added = {list(graph.keys())[0]}
    heap = []
    counter = {}
    for vertex in graph.keys():
        push(heap, (inf, vertex))
        counter[vertex] = inf
    while (len(sub_graph) != len(graph)):
        for edges in sub_graph.values():
            for edge in edges:
                if edge[0] not in added:
                    heap.remove((counter[edge[0]], edge[0]))
                    new_val = min(edge[1], counter[edge[0]])
                    push(heap, (new_val, edge[0]))
                    counter[edge[0]] = new_val
        vertex = pop(heap)
        cost += vertex[0]
        try:
            sub_graph[vertex[1]] = graph[vertex[1]]
        except KeyError:
            pass
        added.add(vertex[1])

    return cost
Exemplo n.º 22
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def func():
    t = int(input())
    res_for_test_cases = []
    for i in range(t):
        n = int(input())
        jobs = []
        for j in range(n):
            jobtemp = input().split()
            jobs.append([int(i) for i in jobtemp])
        totrunningtime = 0
        totalmoney = 0
        jobs = jobs.sorted(key=sortbydeadline)
        priorityq = []
        heapq.heapify(priorityq)
        for job in jobs:
            # heapq.push((job[-1],job[0],job[1]))
            totrunningtime += jobs[1]
            if totrunningtime < job[-1]:
                heapq.push(priorityq, (job[-1], job[0], job[1]))
            else:
                highest_a_job = heapq.pop(priorityq)
                if totrunningtime - highest_a_job[2] < job[-1]:
                    time_to_dec = totrunningtime - job[-1]
                    amount = (highest_a_job[-1] -
                              time_to_dec) / highest_a_job[1]
                    totalmoney += amount
                    heapq.push(priorityq, (highest_a_job[1], highest_a_job[0],
                                           highest_a_job[1] - time_to_dec))
                    print('totalmoney: ', totalmoney)
                    for i in range(t):
                        print(res_for_test_cases[i])

                    func()
Exemplo n.º 23
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def searchEM(board,nodesToExpand=1000):
	startNode = createFunction(board)

	heap = []
	push(heap,(-startNode.score,startNode))
	i = 0
	while i < nodesToExpand:
		start = time.time()
		thisNode = pop(heap)[1]
		if not thisNode.expanded:
			thisNode.expand()
			for a in ['L', 'R', 'D', 'U']:
				for childNode in thisNode.children2[a]:
					push(heap,(-childNode.score,childNode))
				for childNode in thisNode.children4[a]:
					push(heap,(-childNode.score,childNode))
			i += 1
		"""
		else:
			#print (i)
			for a in ['L', 'R', 'D', 'U']:
				for childNode in thisNode.children2[a]:
					push(heap,(-childNode.score,childNode))
				for childNode in thisNode.children4[a]:
					push(heap,(-childNode.score,childNode))
		"""

		#print "time to expand:" , time.time()-start

	Node.allNodes = {}

	#print (startNode.bestDir)
	#pdb.set_trace()
	return move(board,startNode.bestDir)
Exemplo n.º 24
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def bathroom(n, k):
    heap = []
    push(heap, -n)
    for i in range(k - 1):
        num = -pop(heap)
        h = num / 2
        if num % 2 == 0:
            push(heap, -h)
            push(heap, -h + 1)
        else:
            push(heap, -h)
            push(heap, -h)
    num = -pop(heap)
    if num % 2 == 0:
        return num / 2, num / 2 - 1
    return num / 2, num / 2
Exemplo n.º 25
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    def traverser(self, graph, source, dest):
        queue = []
        start_heuristic = float(graph.node[source]['heuristic'])
        # Queue item (heuristic, (node, cost, parent))
        push(queue, (start_heuristic, (source, 0, None)))

        while queue:
            print(queue)
            currentnode, cost, parent = pop(queue)[1]
            print(currentnode)
            # goal check
            if (currentnode == dest):
                self.visited[currentnode] = parent
                self.path = [currentnode]
                origin = parent
                while origin is not None:
                    self.path.append(origin)
                    origin = self.visited[origin]
                self.path.reverse()
                break

            if (currentnode not in list(self.visited.keys())):
                self.visited[currentnode] = parent

            # check neighbours
            # Items returns (neighbornode, {dict of edge attributes})
            for neighbor, data in graph[currentnode].items():
                nheuristic = float(graph.node[neighbor]['heuristic'])
                ncost = cost + float(data['weight'])
                #  creating list with nodes in the queue
                queuenodes = [tuple[1][0] for tuple in queue]
                if (neighbor not in list(self.visited.keys())
                        and neighbor not in queuenodes):
                    # push to the queue with heuristic, cost ,parent
                    push(queue, (nheuristic, (neighbor, ncost, currentnode)))
Exemplo n.º 26
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def traverse(figure, n, m):

    dis = [-1 for i in xrange(n * m)]

    q = []

    G = n * m - 1

    push(q, (0, 0))

    dis[0] = 0

    while (len(q) > 0):

        d, v = pop(q)

        for u in figure[v]:

            if (dis[u] > d + 1) or -1 == dis[u]:

                dis[u] = d + 1

                if u == G:
                    return d + 1

                push(q, (dis[u], u))

    return dis[-1]
Exemplo n.º 27
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def main():
  n = int(sys.stdin.readline().strip())
  coming_up = defaultdict(int)
  vs = []
  leaves = set(range(1,n+2))
  for line in sys.stdin:
    v = int(line.strip())
    coming_up[v] += 1
    vs.append(v)
    if v in leaves:
      leaves.remove(v)

  if vs[-1] != n+1:
    print "Error"
    return

  avail = []
  for i in leaves:
    push(avail, i)

  soln = []
  for i in vs:
    if len(avail) == 0:
      print "Error"
      return
    soln.append(str(pop(avail)))
    coming_up[i] -= 1
    if coming_up[i] == 0:
      push(avail, i)

  print "\n".join(soln)
Exemplo n.º 28
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    def findKthLargest(self, nums, k):
        """
        :type nums: List[int]
        :type k: int
        :rtype: int
        """
        heap = []

        for n in nums:
            if len(heap) < k:
                push(heap, n)
            else:
                if heap[0] < n:
                    pop(heap)
                    push(heap, n)

        return heap[0]
 def kClosest(self, points, K):
     """
     :type points: List[List[int]]
     :type K: int
     :rtype: List[List[int]]
     """
     heap = []
     for x, y in points[:K]:
         push(heap, (-x**2 - y**2, x, y))
     for x, y in points[K:]:
         push(heap, (-x**2 - y**2, x, y))
         pop(heap)
     res = []
     while len(heap) > 0:
         x = pop(heap)
         res.append([x[1], x[2]])
     return res
Exemplo n.º 30
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    def findClosestElements(self, arr: List[int], k: int, x: int) -> List[int]:

        if not arr and len(arr) < 1:
            return

        heap_list = []
        for i in arr:
            heappush(heap_list, MyObject(abs(x - i), i))
            if len(heap_list) > k:
                pop(heap_list)

        result = []
        while len(heap_list) > 0:
            x = pop(heap_list).val
            result.append(x)

        return sorted(result)
Exemplo n.º 31
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def solution(scoville, K):
    answer = 0
    h = []

    for v in scoville:
        push(h, v)

    while len(h) > 0:
        low = pop(h)

        if low >= K:
            return answer
        elif len(h) > 0:
            push(h, low + pop(h) * 2)
            answer += 1

    return -1
Exemplo n.º 32
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def power_sumDigTerm(n):
    h = []
    for b in range(2, 200):
        push_next(b, b, 1, h)
    for k in range(n):
        p, b, e = pop(h)
        push_next(p, b, e, h)
    return p
    def minMeetingRooms(self, intervals: List[List[int]]) -> int:
        if not intervals:
            return 0

        # sort based on start time
        intervals.sort(key=lambda x: x[0])

        room_heap = []
        push(room_heap, intervals[0][1])

        for i in range(1, len(intervals)):

            if intervals[i][0] >= room_heap[0]:
                pop(room_heap)

            push(room_heap, intervals[i][1])

        return len(room_heap)
Exemplo n.º 34
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def Kmost_frequent(word_list, k):
    if not word_list:
        return []

    n_appear = {word_list[0]: 1}
    heap = [(1, word_list[0])]
    for i in range(1, len(word_list)):
        n_appear[word_list[i]] = n_appear.get(word_list[i], 0) + 1
        if len(heap) < k:
            # If it was in the heap, pop it
            heapq.pop((n_appear[word_list[i] - 1, word_list[i]]))
            # add it to the heap
            heapq.heappush(heap, (n_appear[word_list[i]], word_list[i]))
        else:
            # If it was in the heap, pop it
            heapq.pop((n_appear[word_list[i] - 1, word_list[i]]))
            if len(heap) == k:
                heapq.heappop
Exemplo n.º 35
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def AEstrella(origen, funcionParo, g, h):
    '''Función que implementa el algoritmo A*

  Parámetros
  origen: estado desde el que se inicia
  fucionParo: función que nos indica si llegamos a un estado meta
  g: función de costo acumulado
  h: función heuristica

  return solución o nada
  '''
    historia = [(0, 0)]
    # solución trivial
    if funcionParo(origen):
        return trayectoria(origen), historia

    # inicializamos al agenda
    agenda = []

    # inicializamos el conjunto de expandidos
    expandidos = set()

    # generamos la función f(s) = g(s) + h(s)
    # f(s) representa el costo total a un nodo
    # costo acumulado más el costo de la heuristica a ese nodo
    # esto nos representará la prioridad para cada nodo
    f = lambda s: g(s) + h(s)

    # agregamos el primer nodo a la agenda
    push(agenda, (f(origen), origen))

    # mientras existan elementos en la agenda
    while agenda:
        historia.append((len(agenda), len(expandidos)))
        # sacamos un nodo de la agenda
        nodo = pop(agenda)[1]  # pos 1 para obtener el estado de la tupla

        # lo agregamos al conjunto de expandidos
        expandidos.add(nodo)

        # comparamos si este nodo cumple con la función de paro
        if funcionParo(nodo):
            return trayectoria(nodo), historia
        '''Comparamos si el nodo cumple con la función de paro aquí dado que el 
    algoritmo termina cuando el nodo objetivo o estado meta se encuentra en 
    la cabeza de la cola de prioridad, esto ocurrirá cuando el nodo sea el 
    siguiente en salir, por eso se compará afuera del ciclo'''
        # expandimos el nodo y comparamos a sus hijos
        for hijo in nodo.expandir():

            # agregamos el hijo a la cola de prioridad
            # siempre y cuando no esté en el conjunto de expandidos
            if hijo not in expandidos:
                push(agenda, (f(hijo), hijo))

    # si no hay ruta, regresamos un vacio
    return
Exemplo n.º 36
0
def kNearestPoints(points, k):
    heap = []
    result = []
    for i in range(len(points)):
        x, y = points[i]
        dist = x * x + y * y
        push(heap, (dist, points[i]))
    for j in range(k):
        result.append(pop(heap)[1])
    return result
Exemplo n.º 37
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 def predict(self, new_X, k, dist_measure):
     assert k > 0
     assert dist_measure in dist_measures
     heap = []
     new_X = (new_X - self.means) / self.stds
     for i in range(len(self.X)):
         dist = dist_measures[dist_measure](self.X[i], new_X)
         push(heap, (dist, i))
     labels = list(map(lambda i: self.Y[pop(heap)[1]], range(k)))
     return np.bincount(labels).argmax()
Exemplo n.º 38
0
 def predict(self, new_X, k, dist_measure):
     assert k > 0
     assert dist_measure in dist_measures
     heap = []
     new_X = (new_X - self.means) / self.stds
     for i in range(len(self.X)):
         dist = dist_measures[dist_measure](self.X[i], new_X)
         push(heap, (dist, i))
     labels = list(map(lambda i: self.Y[pop(heap)[1]], range(k)))
     return np.bincount(labels).argmax()
Exemplo n.º 39
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def Astar(start,goal):
  q = [start]
  visited = {}
  while q:
    node = pop(q)
    if node == goal:
      return node
    for step in node.steps():
      if step not in visited or visited[step] > step:
        push(q,step)
        visited[step] = step
Exemplo n.º 40
0
def dijkstra(g,raizes):
    '''
    Parametro: g, representando um grafo
    Retorno: arvore, arvore de caminhos minimos
    Função: Retorna a SPT (Shortest Path Tree) ou arvore de caminhos minimos
    do grafo recebido como parametro
    '''
    lista_prioridades = [(Inf,i) for i in range(int(nx.number_of_nodes(g)))]
    # lista_prioridades transformar em heap
    heapify(lista_prioridades) 
    # inserir nó 0 (assumindo que o nó 0 é a raiz) com prioridade 0
    for i in raizes:    
        push(lista_prioridades, (0, i))
    #representação: posterior é o indice e anterior é o valor armazenado
    anteriores = [None for i in range(int(nx.number_of_nodes(g)))]
    # cria um dicionário que indica se um vertice v está no heap (se está no heap, ainda não foi processado)
    inheap = { v: True for v in g.nodes() }
    # cria um dicionário de pesos
    pesos = { v: float('inf') for v in g.nodes() }
    for i in raizes:    
        pesos[i] = 0;
 
    while lista_prioridades:
        no = pop(lista_prioridades)
        # testa se no ainda não foi removido do heap anteriormente (como não podemos atualizar os pesos, um nó pode repetir)
        if (inheap[no[1]]):
            inheap[no[1]] = False # foi retirado do heap pela primeira vez
        else:
            continue # já foi retirado do heap antes (repetido)

        #Seleciona cada vizinho
        for i in nx.neighbors(g,no[1]):
            #verifica se vizinho esta na lista de prioridades            
            if (inheap[i]): 
                #verifica se um no é anterior do outro   
                peso = g.get_edge_data(no[1],i)['weight'] + no[0]
                if peso < pesos[i]:
                    push(lista_prioridades, (peso, i))
                    anteriores[i] = no[1]
                    pesos[i] = peso
                
    arestas = [(i,anteriores[i]) for i in range(len(anteriores))]
    nos = []    
    for i in raizes:
        if (i,None) in arestas:
            nos.append(i)
			#Remove arestas que ligam um grafo a None
            arestas.remove((i,None))
    #arestas.pop(0) #Descarta o primeiro pois é a aresta da raiz, que não se liga com ninguém (0,None)
    g.clear()
    g.add_edges_from(arestas)
	#Coloca os nós que ficaram sozinhos
    g.add_nodes_from(nos)
    return g
Exemplo n.º 41
0
def Prim(g,dic_pesos):
    '''
    Parametro: g, representando um grafo
    Retorno: arvore, arvore geradora minima
    Função: Retorna a MST (Minimun Spend Tree) ou arvore geradora minima
    do grafo recebido como parametro
    '''
    lista_prioridades = [(Inf,i) for i in range(int(nx.number_of_nodes(g)))]
    # lista_prioridades transformar em heap
    heapify(lista_prioridades) 
    # inserir nó 0 (assumindo que o nó 0 é a raiz) com prioridade 0
    push(lista_prioridades, (0, 0))
    #representação: posterior é o indice e anterior é o valor armazenado
    anteriores = [None for i in range(int(nx.number_of_nodes(g)))]
    # cria um dicionário que indica se um vertice v está no heap (se está no heap, ainda não foi processado)
    inheap = { v: True for v in g.nodes() }
    # cria um dicionário de pesos (evita a necessidade de utilizar a função verifica_vizinho)
    pesos = { v: float('inf') for v in g.nodes() }
    pesos[0] = 0;
 
    while lista_prioridades:
        no = pop(lista_prioridades)
        # testa se no ainda não foi removido do heap anteriormente (como não podemos atualizar os pesos, um nó pode repetir)
        if (inheap[no[1]]):
            inheap[no[1]] = False # foi retirado do heap pela primeira vez
        else:
            continue # já foi retirado do heap antes (repetido)

        #Seleciona cada vizinho
        for i in nx.neighbors(g,no[1]):
            #verifica se vizinho esta na lista de prioridades            
            if (inheap[i]): 
                #verifica se um no é anterior do outro   
                peso = dic_pesos[(no[1],i)]
                if peso < pesos[i]:
                    push(lista_prioridades, (peso, i))
                    anteriores[i] = no[1]
                    pesos[i] = peso
                    
    arestas = [(i,anteriores[i]) for i in range(len(anteriores))]
    arestas.pop(0) #Descarta o primeiro pois é a aresta da raiz, que não se liga com ninguém (0,None)
    g.clear()
    g.add_edges_from(arestas)
    return g
Exemplo n.º 42
0
Arquivo: wc.py Projeto: anchikam/wc
def run_medians(numlist):
    """ Given a list of integers, returns a generator of running medians.
    The method uses 2 heaps (max heap/min heap) and places streaming numbers in either of the 
    heap depending on their values. The way median is found depends if the heaps are balanced or not. """
    itnum = iter(numlist)
    less, more = [], []   
    first = next(itnum)
    yield first
    second = next(itnum)
    push(less, - min(first, second))
    push(more, max(first, second))
    while True:
        curr = ( more[0] if len(less) < len(more)
                    else - less[0] if len(less) > len(more)
                    else (more[0] - less[0]) / 2.0 )
        yield curr
        it = next(itnum)
        if it <= curr: push(less, - it)
        else: push(more, it)
        small, big = ( (less, more) if len(less) <= len(more)
                       else (more, less) )
        if len(big) - len(small) > 1: push(small, - pop(big))
Exemplo n.º 43
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 def pop(self):#pop the smallest item
     key, item = heapq.pop(self.dat);
     return item;