結果

問題 No.1638 Robot Maze
コンテスト
ユーザー 👑 obakyan
提出日時 2021-08-06 21:50:11
言語 Lua
(LuaJit 2.1.1734355927)
結果
AC  
実行時間 21 ms / 2,000 ms
コード長 2,992 bytes
コンパイル時間 360 ms
コンパイル使用メモリ 5,248 KB
実行使用メモリ 5,376 KB
最終ジャッジ日時 2024-09-17 01:44:07
合計ジャッジ時間 1,396 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge3
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 * 3
other AC * 49
権限があれば一括ダウンロードができます

ソースコード

diff # 

local mfl, mce = math.floor, math.ceil
local mmi, mma = math.min, math.max
local pow2 = {1}
for i = 2, 28 do pow2[i] = pow2[i - 1] * 2 end
local SegTree = {}
SegTree.updateAll = function(self)
  for i = self.stagenum - 1, 1, -1 do
    local cnt = pow2[i]
    for j = 0, cnt - 1 do
      self.stage[cnt + j] = self.func(self.stage[(cnt + j) * 2], self.stage[(cnt + j) * 2 + 1])
    end
  end
end
SegTree.create = function(self, n, func, emptyvalue)
  self.func, self.emptyvalue = func, emptyvalue
  local stagenum, mul = 1, 1
  self.stage = {} -- use 1D Tree (stage[], not stage[][])
  while mul < n do
    mul, stagenum = mul * 2, stagenum + 1
  end
  self.stagenum = stagenum
  for i = 1, mul * 2 - 1 do self.stage[i] = emptyvalue end
  for i = 1, n do self.stage[mul + i - 1] = i end
  self:updateAll()
end
SegTree.update = function(self, idx, force)
  idx = idx + pow2[self.stagenum] - 1
  for i = self.stagenum - 1, 1, -1 do
    local dst = mfl(idx / 2)
    local rem = dst * 4 + 1 - idx
    self.stage[dst] = self.func(self.stage[idx], self.stage[rem])
    if not force and self.stage[dst] ~= self.stage[idx] then break end
    idx = dst
  end
end
SegTree.new = function(n, func, emptyvalue)
  local obj = {}
  setmetatable(obj, {__index = SegTree})
  obj:create(n, func, emptyvalue)
  return obj
end

local h, w = io.read("*n", "*n")
assert(1 < h and 1 < w)
local c_up, c_down, c_right, c_left = io.read("*n", "*n", "*n", "*n")
local klim, p = io.read("*n", "*n")
local xs, ys = io.read("*n", "*n")
local xt, yt = io.read("*n", "*n", "*l")
local map = {}
for i = 1, h do
  local s = io.read()
  map[i] = {}
  for j = 1, w do
    map[i][j] = s:sub(j, j)
  end
end
local n = h * w
local inf = klim + 1
local len = {}
local asked = {}
for i = 1, n do
  len[i] = inf
  asked[i] = false
end
local spos = (xs - 1) * w + ys
len[spos] = 0
asked[n + 1] = true

local function mergefunc(x, y)
  if asked[x] then return y
  elseif asked[y] then return x
  else
    return len[x] < len[y] and x or y
  end
end

local st = SegTree.new(n, mergefunc, n + 1)

local function walk(src, dst)
  local dst_row = mce(dst / w)
  local dst_col = dst - (dst_row - 1) * w
  local cost = 0
  if src + 1 == dst then cost = c_right
  elseif src - 1 == dst then cost = c_left
  elseif src + w == dst then cost = c_down
  elseif src - w == dst then cost = c_up
  else
    assert(false)
  end
  if map[dst_row][dst_col] == "#" then return end
  if map[dst_row][dst_col] == "@" then cost = cost + p end

  if len[src] + cost < len[dst] then
    len[dst] = len[src] + cost
    st:update(dst)
  end
end

for i = 1, n do
  local src = st.stage[1]
  if asked[src] then break end
  if inf <= len[src] then break end
  asked[src] = true
  st:update(src, true)
  if src % w ~= 1 then walk(src, src - 1) end
  if src % w ~= 0 then walk(src, src + 1) end
  if w < src then walk(src, src - w) end
  if src <= (h - 1) * w then walk(src, src + w) end
end

local tpos = (xt - 1) * w + yt
print(len[tpos] <= klim and "Yes" or "No")
0