Streaming pairwise implementation

pairwise.py

import random
import time

def counts_to_pairs(counts, target):
  pairs, incomplete = {}, {}
  for a in range(int(target/2)+1):
    b = target-a
    matching_pair = counts.get(a,0) >= 1 and counts.get(b, 0) >= 1
    if matching_pair:
      if a == b: 
        # special case for midpoint
        pairs[(a,b)] = int(counts[a]/2)
        incomplete[a] = counts[a]%2
      else:
        pairs[(a,b)] = min(counts[a], counts[b])
        incomplete[a] = max(counts[a] - counts[b], 0)
        incomplete[b] = max(counts[b] - counts[a], 0)
    else:
      incomplete[a] = counts.get(a,0)
      incomplete[b] = counts.get(b,0)
  return pairs, incomplete  


class Pairwise():
  def __init__(self, target) -> None:
    self.counts = {}
    self.target = target
    self.start = time.time()

  def next_num(self, number):
    if number not in self.counts:
      self.counts[number] = 0
    self.counts[number] += 1

  def short_stats(self):
    pairs, incomplete = counts_to_pairs(self.counts, self.target)
    total_pairs = sum(pairs.values())
    return f"Number of pairs: {total_pairs}"

  def print_results(self):
    pairs, incomplete = counts_to_pairs(self.counts, self.target)
    self.end = time.time()

    print("Unmatched:")
    for k in sorted(incomplete):
      if incomplete[k]>0:
        print(f"   {k}: {incomplete[k]}")

    print("Complete Pairs:")
    for k in sorted(pairs):
      if pairs[k]>0:
        print(f"   {k}: {pairs[k]}")

    print()
    print(f"Executed in {self.end - self.start} seconds")
    print("===")

def progress_meter(count, total, additional_string_fn=lambda:""):
  width = 60
  resolution = int(total/(width*4))
  if count%resolution !=0:
    return
  charlen = int(count*width/total)
  sequence = "-\\|/"
  s = int(count/resolution)%4
  percent = (count/total) * 100
  print('\r', "|", "-"*charlen, sequence[s], "."*(width-charlen-1), "|", f"{percent:.2f}% {additional_string_fn()}", end="", flush=True)

def main():
  # Example that was given
  numbers = [1,12,4,6,8,5,7,12,11,6,7,5,0,6,6]
  p1 = Pairwise(target=12)
  for number in numbers:
    p1.next_num(number)
  p1.print_results()

  # Many random numbers
  p2 = Pairwise(target=12)
  total = 10000000
  print(f"Running {total} numbers")
  for count in range(total):
    progress_meter(count, total, p2.short_stats)
    number = random.randint(0,12)
    p2.next_num(number)
  print()
  p2.print_results()

if __name__ == "__main__":
  main()