just for fun captcha solver for code challenge

captcha_solver.py

def solve_captcha(sequence):
    return sum(
        int(num) for i, num in enumerate(sequence) if num == sequence[(i+1) % len(sequence)]
    )

assert solve_captcha('1122') == 3
assert solve_captcha('1111') == 4
assert solve_captcha('1234') == 0
assert solve_captcha('91212129') == 9

sequence = '3801219356208138590410639949502922324758870956901034391673799018355647790565877097195839447540715564272571483487956780824953658829135545484059928411675056348415711573285456843872061893305099849813733887049254118252931250950553524728357672662214635748158436021219711283189827562053402598336411051488102965027876043723951010003925195389132557334026742444154387486314469312232719954644805681399271596840033764549177793261113525450924586619784251686652364931747953378089212551908515581599501188912896127337722907992361449678187290503180583991009524375784935707382892678629672965456641020695820138089004237819736874474190685803639253938668337043493403375869310881448009873269985430793208961281808497096847394012898904160470106518410310865842857977602374474348041345223089044998026993954285652178380101608276937031189381098461498787923568439791839850187503817155425146172789017084716643322925503362778565054434826752677047839408555993717139723488535519408425976810984504990390432419671238442486883896585891797710825023569194944160375311421902050684850312420951140205552297164465181103684324995262677582949328937688882211798032308046835473981424317308399496561612275061014885407552118703142255703410994144508738418468591885426566198220135286690633105019982233508563393175221668957425331043484742299730798102044092168051162105031517863799138585595736669000095454744720828744625239571148450753555397894155872393959054856564726997179430842473548855603673402362663812823929672044320408053576302637189523709652947963273624584196806556349547404138293414809236518439748255884392857670837141288203468593005285515493881551777814515350551214296568069867749466009994142929581886406159386005962044366907184227451001992532845725294289407994957472542532475757221649139349903358223668812386217226414377883546352408108341186423317410125198781095718979512223746457244790301637528476079743219219146622644424098047690439675699391108514724881126840620007189969389540326196565092953166912397015353401475448399920639190386164563771284459430959'

print(solve_captcha(sequence))
# >> 987