s840.py

from research import *
s=begin(840,'Regenerate the complete reverse-order festival path','What relation joins the two declared orders at every boundary?',{},['File58 §7.2; C839'])
p=json.loads((ROOT/'model/list_inputs.json').read_text());f=json.loads((ROOT/'model/festival_forward_path.json').read_text());v=f['weights'][::-1]
pre=[sum(v[:k]) for k in range(9)];coords=[1859-7*x for x in pre]
a=artifact('model/festival_reverse_path.json',json.dumps({'weights':v,'prefix_counts':pre,'BC':coords},indent=2)+'\n')
finish(s,{'path':a,'prefix_counts':pre,'BC':coords,'paired_formula':'reverse_prefix(k)=199−forward_prefix(8−k)','coordinate_pair_sum':2*1859-7*199},'Every reverse boundary is the complement of a corresponding forward boundary. This is a sequence-reversal relation on two paths, not a newly licensed formal Mirror operation.','Identify exactly where the two source orders share boundaries.',{'literal_dates':coords[1:]==[int(x['cells'][4].split()[0]) for x in p['tables']['reverse']['rows']],'whole_complement':all(pre[k]==199-f['prefix_counts'][8-k] for k in range(9))})