proc intervalInsert(intervals: var seq[tuple], interval: tuple) =
  var i = -1
  var a = interval[0]
  var b = interval[1]
  var ni = (0, 0)
  var last: int
  var pos = -1
  while i < intervals.len:
    inc(i)
    var min = intervals[i][0]
    var max = intervals[i][1]
    if pos == -1:
      if a > max: continue
      elif a >= min and a <= max:
        ni[0] = min
      elif a > min:
        ni[0] = a
      pos = i
    else:
      if b > max:
        continue
      elif b >= min and b <= max:
        ni[1] = max
      elif b < min:
        ni[1] = b
      last = i
      break

  for d in countdown(last, pos):
    intervals.delete(d)
  intervals.insert(ni, pos)

var ivals = @[(1, 3), (6, 9)]
var nival = (2, 5)

echo ivals, " ", nival
ivals.intervalInsert(nival)
echo ivals


ivals = @[(1,2),(3,5),(6,7),(8,10),(12,16)]
nival = (4, 8)

echo ivals, " ", nival
ivals.intervalInsert(nival)
echo ivals

#output -> ((1,5), (6,9))

#[
((a1,b1), (a2,b2), (an, bn))

(a, b)

loop thru interval list where n is current value and is either a min or max
  if a > n then continue else
    if a is min then
    if a is max then


if a inrange of an, bn
then find
  where b falls in interval list
    check every number, n, in the interval list
    if passed interval delete interval
    if b <= n
      if n is min
when is inrange of an, bn
]#