Problem:
Score : 400 points

Problem Statement

One day, Snuke was given a permutation of length N, a_1, a_2, ..., a_N, from his friend.

Find the following:

Constraints

1 ≦ N ≦ 200,000

(a_1, a_2, ..., a_N) is a permutation of (1, 2, ..., N).

Input

The input is given from Standard Input in the following format:

N
a_1 a_2 ... a_N

Output

Print the answer.

Note that the answer may not fit into a 32-bit integer.

Sample Input 1

3
2 1 3

Sample Output 1

9

Sample Input 2

4
1 3 2 4

Sample Output 2

19

Sample Input 3

8
5 4 8 1 2 6 7 3

Sample Output 3

85

Solution in LuaJIT (2.0.4) (judge verdict: Accepted)

local mfl, mce = math.floor, math.ceil
local mmi, mma = math.min, math.max
local bls, brs = bit.lshift, bit.rshift
-- local pow2 = {1}
-- for i = 2, 26 do
--   pow2[i] = 2 * pow2[i - 1]
-- end
-- local function bls(a, b)
--   return a * pow2[b + 1]
-- end
-- local function brs(a, b)
--   return a // pow2[b + 1]
-- end

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.setValue = function(self, idx, value, silent)
  self.stage[self.stagenum][idx] = value
  if not silent then
    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
end
SegTree.right_bound = function(self, val, left, right)
  local ret, retpos = self.emptyvalue, left - 1
  local l, r = left, right
  local stage = mma(self.left_stage[left], self.sz_stage[right - left + 1])
  local stagenum = self.stagenum
  while true do
    local sz = bls(1, stagenum - stage)
    local tmp = self.func(ret, self.stage[stage][mce(l / sz)])
    if tmp < val then
      ret, retpos = tmp, l + sz - 1
      if retpos == right then break end
      if l + sz <= r then
        l = l + sz
        stage = mma(self.left_stage[l], self.sz_stage[r - l + 1])
      else break end
    else
      if sz ~= 1 then stage, r = stage + 1, l + sz - 2
      else break end
    end
  end
  return retpos + 1
end
SegTree.left_bound = function(self, val, left, right)
  local ret, retpos = self.emptyvalue, right + 1
  local stage, l, r = 1, left, right
  local stagenum = self.stagenum
  while true do
    local sz = bls(1, stagenum - stage)
    while r % sz ~= 0 or r + 1 - l < sz do
      stage = stage + 1
      sz = bls(1, stagenum - stage)
    end
    local tmp = self.func(ret, self.stage[stage][mfl(r / sz)])
    if tmp < val then
      ret, retpos = tmp, r - sz + 1
      if l + sz <= r then stage, l, r = 1, l, r - sz
      else break end
    else
      if sz ~= 1 then stage, l, r = stage + 1, r - sz + 2, r
      else break end
    end
  end
  return retpos - 1
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 st = SegTree.new(n, mma, -n-1)
local invpos = {}
for i = 1, n do invpos[i] = i end
for i = 1, n do
  local z = io.read("*n")
  st:setValue(i, -z, true)
  invpos[z] = i
end
st:updateAll()
local ret = 0LL
for i = 1, n do
  local pos = invpos[i]
  local rb = st:right_bound(-i + 1, pos, n)
  local lb = st:left_bound(-i + 1, 1, pos)
  ret = ret + 1LL * i * (rb - pos) * (pos - lb)
end
local str = tostring(ret):gsub("LL", "")
print(str)