local mfl, mce = math.floor, math.ceil local mmi, mma = math.min, math.max local bls, brs = bit.lshift, bit.rshift local SegTree = {} SegTree.updateAll = function(self) for i = self.stagenum - 1, 1, -1 do local cnt = bls(1, i - 1) for j = 1, cnt do self.stage[i][j] = self.func(self.stage[i + 1][j * 2 - 1], self.stage[i + 1][j * 2]) end end end SegTree.create = function(self, n, func, emptyvalue) self.func, self.emptyvalue = func, emptyvalue local stagenum, mul = 1, 1 self.stage = {{}} while mul < n do mul, stagenum = mul * 2, stagenum + 1 self.stage[stagenum] = {} end self.stagenum = stagenum self.left_stage = {} for i = 1, n do local sp, sz = 1, bls(1, stagenum - 1) while(i - 1) % sz ~= 0 do sp, sz = sp + 1, brs(sz, 1) end self.left_stage[i] = sp end self.sz_stage = {} local tmp, sp = 1, stagenum for i = 1, n do if tmp * 2 == i then tmp, sp = tmp * 2, sp - 1 end self.sz_stage[i] = sp end for i = 1, mul do self.stage[stagenum][i] = emptyvalue end self:updateAll() end SegTree.getRange = function(self, left, right) if left == right then return self.stage[self.stagenum][left] end local stagenum = self.stagenum local ret = self.emptyvalue while left <= right do local stage = mma(self.left_stage[left], self.sz_stage[right - left + 1]) local sz = bls(1, stagenum - stage) ret = self.func(ret, self.stage[stage][1 + brs(left - 1, stagenum - stage)]) left = left + sz end return ret end SegTree.update = function(self, idx) for i = self.stagenum - 1, 1, -1 do local dst = brs(idx + 1, 1) local rem = dst * 4 - 1 - idx self.stage[i][dst] = self.func(self.stage[i + 1][idx], self.stage[i + 1][rem]) idx = dst end end SegTree.setValue = function(self, idx, value, silent) self.stage[self.stagenum][idx] = value if not silent then self:update(idx) end end SegTree.new = function(n, func, emptyvalue) local obj = {} setmetatable(obj, {__index = SegTree}) obj:create(n, func, emptyvalue) return obj end local n = io.read("*n") local edge = {} local cost = {} local asked = {} local cpos = {} local len = {} local stpos = {} local score = {} for i = 1, n do edge[i] = {} cost[i] = {} asked[i] = false cpos[i] = 0 len[i] = 0 stpos[i] = 0 score[i] = 0 end len[n + 1] = 1000000007 for i = 1, n - 1 do local x, y = io.read("*n", "*n") local c = io.read("*n") table.insert(edge[x], y) table.insert(edge[y], x) table.insert(cost[x], c) table.insert(cost[y], c) end local st = SegTree.new(2 * n - 1, function(a, b) return len[a] < len[b] and a or b end, n + 1) local tasks = {1} local sti = 1 while 0 < #tasks do local src = tasks[#tasks] table.remove(tasks) asked[src] = true -- print(src, len[src]) stpos[src] = sti st:setValue(sti, src, true) sti = sti + 1 while cpos[src] < #edge[src] do cpos[src] = cpos[src] + 1 local dst = edge[src][cpos[src]] if not asked[dst] then len[dst] = len[src] + 1 score[dst] = score[src] + cost[src][cpos[src]] table.insert(tasks, src) table.insert(tasks, dst) break end end end st:updateAll() local q = io.read("*n") for iq = 1, q do local a, b = io.read("*n", "*n") local sta, stb = stpos[a], stpos[b] if stb < sta then sta, stb = stb, sta end local p = st:getRange(sta, stb) print(score[a] + score[b] - score[p] * 2) end