結果

問題 No.2739 Time is money
ユーザー tufusa
提出日時 2025-04-17 17:20:07
言語 Ruby
(3.4.1)
結果
AC  
実行時間 1,784 ms / 2,000 ms
コード長 3,054 bytes
コンパイル時間 493 ms
コンパイル使用メモリ 8,356 KB
実行使用メモリ 76,800 KB
最終ジャッジ日時 2025-04-17 17:20:37
合計ジャッジ時間 25,370 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 18
権限があれば一括ダウンロードができます
コンパイルメッセージ
Syntax OK

ソースコード

diff # 

# Priority Queue
# Reference: https://github.com/python/cpython/blob/main/Lib/heapq.py
class PriorityQueue
  # By default, the priority queue returns the maximum element first.
  # If a block is given, the priority between the elements is determined with it.
  # For example, the following block is given, the priority queue returns the minimum element first.
  # `PriorityQueue.new { |x, y| x < y }`
  #
  # A heap is an array for which a[k] <= a[2*k+1] and a[k] <= a[2*k+2] for all k, counting elements from 0.
  def initialize(array = [], &comp)
    @heap = array
    @comp = comp || proc { |x, y| x > y }
    heapify
  end

  def self.max(array)
    new(array)
  end

  def self.min(array)
    new(array) { |x, y| x < y }
  end

  def self.[](*array, &comp)
    new(array, &comp)
  end

  attr_reader :heap
  alias to_a heap

  # Push new element to the heap.
  def push(item)
    shift_down(0, @heap.push(item).size - 1)
    self
  end

  alias << push
  alias append push

  # Pop the element with the highest priority.
  def pop
    latest = @heap.pop
    return latest if empty?

    ret_item = heap[0]
    heap[0] = latest
    shift_up(0)
    ret_item
  end

  # Get the element with the highest priority.
  def get
    @heap[0]
  end

  alias top get
  alias first get

  # Returns true if the heap is empty.
  def empty?
    @heap.empty?
  end

  def size
    @heap.size
  end

  def to_s
    "<#{self.class}: @heap:(#{heap.join(', ')}), @comp:<#{@comp.class} #{@comp.source_location.join(':')}>>"
  end

  private

  def heapify
    (@heap.size / 2 - 1).downto(0) { |i| shift_up(i) }
  end

  def shift_up(pos)
    end_pos = @heap.size
    start_pos = pos
    new_item = @heap[pos]
    left_child_pos = 2 * pos + 1

    while left_child_pos < end_pos
      right_child_pos = left_child_pos + 1
      if right_child_pos < end_pos && @comp.call(@heap[right_child_pos], @heap[left_child_pos])
        left_child_pos = right_child_pos
      end
      # Move the higher priority child up.
      @heap[pos] = @heap[left_child_pos]
      pos = left_child_pos
      left_child_pos = 2 * pos + 1
    end
    @heap[pos] = new_item
    shift_down(start_pos, pos)
  end

  def shift_down(star_pos, pos)
    new_item = @heap[pos]
    while pos > star_pos
      parent_pos = (pos - 1) >> 1
      parent = @heap[parent_pos]
      break if @comp.call(parent, new_item)

      @heap[pos] = parent
      pos = parent_pos
    end
    @heap[pos] = new_item
  end
end

n, m, x = gets.split.map(&:to_i)
paths = m.times.map { gets.split.map(&:to_i) }
g = Array.new(n) { [] }
paths.each do |u, v, c, t|
  cost = t * x + c # cost = time * x
  g[u - 1] << [v - 1, cost]
  g[v - 1] << [u - 1, cost]
end

inf = 10**20
dist = Array.new(n, inf).tap { _1[0] = 0 }
que = PriorityQueue.new { _1[0] < _2[0] }

que << [0, 0]
until que.empty?
  cost, now = que.pop
  next if cost > dist[now]

  g[now].each do |nxt, c|
    cnx = cost + c
    next if dist[nxt] <= cnx

    dist[nxt] = cnx
    que.push [cnx, nxt]
  end
end

puts dist[-1] == inf ? -1 : Rational(dist[-1], x).ceil
0