Question

我写了一个脚本从上到下读取一个大字符串，而不是从左到右。当我运行代码时，我的CPU的一个内核钉住@ 100％并且代码永远不会完成。如果我取消注释掉console.log，它会慢慢地将字母吐出来并将所有8个内核固定在100％上，内存使用量会慢慢上升，直到它在我的系统上耗尽所有8GB然后崩溃并出现OOM错误。我显然做了一些可怕的错误。

var haystack = 'SRASBPETHWTWHDZVPOAECJHGNXHRKZXRBMSDYGZGNZBBCOKVPPJKKAQECOLGBFIIKTPVSROCCWWGRWDEQTNFSKEDNFBFKWVEELVTBULWROMGTXSASKCTFJQFDOGRNMZEBLFSCFAFWXZVRGFAZHERUTMOETZZRYNUHSRTHEYIVQDXFNWDDSLSSGPFOMYRHBGKONPIWDTZUBBRAJZGBVUGMVZZTPRAXMLZSXYELKJZWXUYUQIUGGHISZHIGSUQHGHTICVWIJVXMUXOQHPDESKSPRJHQVVTRTNQEVUWKGGQDURAXZWTMYUYIISIOXLTHCISFFSNHZMCGEWMOWCHRQKYNDTDLFWERZLEPRLTNZSPFEDCDESQVMLWMXGCXPMSPTJGSXTXINFADZTBUNDIQWOAIGFKQAJWHINHMZCZVMTJJWGTSGGOIBOZCJGVURJETNXSXWEDUNJPVLPZTDIMSIZGQUJALJYWVLRDYDRWVHZNUNKOLAUPTBMKUNFQYLVQKOQIPPWVNDXENRCVABOTNEKKJPURYNAWAGIZFEHYQMOFICBCQKELTMUYVQPYPZKVBYPTLXRLMYEXGAPRCWDJHQASDQHRGSTIYGMEAWOBLFPSDBGGXFBGIARMGLYOFCZXILLFLCVKCKCXYBTKIYRHLPWXBNGLJYVIZHWPIQSQLHURYRRTBTUBYRMMEQULVVJFKRRZTZVOIKNXPIICBQGFPTETWVPVUKEQOVTCOUARDTAVZFSZWBSTWTQEGLIDKUVMTFRXHOWPPJHCEWMTHJRKXENFENKDMPEYVNEMQRDBGZDIBVYCCFLFMFPSXHHADOZWMMOJKQSYNAPOKLUPSALZVKPKVBRIAFOXSECFCULWPFNPKFGIBPAUEXEOHLTRWTLJMHEMIXSVZVRYZQXCUGNZGDSLXJSROSBAIWPKQGICVKSMAVUHZPIQHDQGLSMJUQYYAZQSVORXLRNMEOYUFAKGKHJFKQPBYKDSLYHKLCEWAQINPRGOGVCQBAKTVDZZNRSIKZVSRMFCDJSANSGNQZPPEZSIZCSQCPMIRBKJZFKVRVVNOLDSYGFLMNJHCGUZDRVHTLSJMCHZCQJUURVMEFABDKQEFYXYZEQUOLEOZWXDXXOXIFPLTFBGTKYTBVSSTJESKVIMHJSUDVKRKOJYOGWIXLODESHRMPYBWKRPFEUGIYXXGHDVYXPUBVSQPHRUSSCQDHAXMJNUNSFGHZANXDFFXDETLXVAUAPOCASOTONXBXIYFMSMUUPFGMYKWVFGTTQFSNUDFTIRWSVVEQHPVFRYPLGPGIEUMSSFONCONOPHSDWGFBIGPEKQBRPZWYLZLKCMWFOKLNQBYJREVFRLWFBDVIVIIVZUTQZOLDSNDUISKYGJTIGWYUQBXXTAPQMKULPXGCYFMZLNQDAWOBWOVTKXOABKZRWAZUDYYTYNDQAEJHEDPOYUANKWMUATXGCRRGEKDVTIGTFLQHQVFJBRIFKYLHDJUXLAMVELRZPNBSEBQUVHARMKVCLLDHHYYQNTXFIMFKRIMTJUEJOWIEIETZDADSGNJFDGGWKRJUXQXXKLOUSYMCTHLYIXSICFCRHFCXUSFOMCVSVYIIMCNEGHRMCZKWXPHFAMCTCBEBHQOBDXHAYNSVVZWAGTEIMVWRCCPNCCQGUWXIGCPZERUVJRQIZQYSMAUNHCVNROCDFORLNOWTLVTHADALVCOISZDFKNFMXQBMVUMFDFKDGNRQKZPXDJNZODBXFUAGEPCEQSLGAOSQZUHJXEQFTRLAWZUUROTADFEXJBGJCOPLRNLLHVTNPNPHJDYWEGBKVOZOFDYMYMHUNDMLIZOCLODMRBZORXZVTUAIDXZIGOLLMGUJLSOHSVDFEMDTXEUMIOITNSXVNXUWMNPFITZXAJBKUVMNLUOONUDQSWYUCZOZXOXAFRCWVMMBLFCPPHFTLEKHXQNWYMQYDLGHTSSGDCFIRSMVTJFKPLVLBWIFWBJQTKXBIMLRTGNABJDXWIEFLVCDLQTSWURMBASDXNXHBQTEBCUTGWVTHXDHRJYZZKNQEBPXRYMWAXEGRSRUCQHYIOVOYJUXPANVEAJEUKKYAWEZSPZYCQPPWXVNNPHIVSHSSYVJLUNDXAFPCXLOOTRYVLVGNIQVPZLBXAPWQGSCCXINWFTIVFGLMUTPRWQFJORMQYYIUUJZRLLFXATWFRCQDKDIFXZHCWJGYEROPRQTJGJJSTRRKAMAGGMZKKOPXYKUSNZVVHHNRAGAGWXZOIYKVMAQJELXWGUEWMTSJMOEZRUEGUBZELODZNCDASJZGOTXYZGVTVMRTVVSWHFEFVUJPCCGEJXWYYLBVZGIGCHRNQOEDELTDIUZPAGGJYPCEEKZNQSMDKNMRZFVBPLIRBFCCVLUGCVPLOPCWDZJZAMKFKRLXTKQJIZSNAQFUXMCLXPTBKNNWWKKBVLYQPFHVEHGXQEHPOWRIIWXGKVBFMMDOJNFMCCNWTALOTLCMFKXKGIKYHQIOUJOAIXEFIMWMKCTABKRCVTAFDLWIQFDUEYDOBFJOKXBKIIBCVIVILAWTFXHLUVTMGQEJEVKBAVMITJPVRGRCDSFLPXRFWGAJLGMSPAOUVMDUBXYWEOVMDNUOIMXGEVNKCALLWPPMNNMFOVTZOAPSDJFZECSDIHKXCYJCAGYKLPOWFTVSRDSBSGGWDNFSTRZQYKMOUDNTRGXFKJBLOECLUJQGRQWGUETMKOGUWCAHDHGGCBSWXTXMLJMJFJTKURTTCXNOOEBYYUVKPWXSNUKVCZOXJOMXXCLTZWBUDYMEJNTIPBTWJKJJLYQFGYRGYFUCTAICLKBYEHONSPSMXLLMZCMJQVOGKEZOYBDJIUHAFGCEIAPXAQVGSBIJVUDHTWPPEKMWWFEUCAQWFRHLCFTLPXVJNKFCTEXGKPZXQXOBKPDWOAFOZTBYGDVFAJXMQOHAPTLSNLKJIGZRFSBGMQBNBAHELRDEWUEWQVKVYZBPGQVOWYKZEGLJRLYHBETRZTEWBTGJBRUTBKNDGEAQEUTLZZSAMCMMVJWBPDKOSGPLVUKPZAQGJDKUIIPCVBOIBCXRAAANQSCBBYQNXRTCRNHJGMRYICLHDBXVXEGBFAEXOAABYDXFQTKPXVMQPHXLTXCVMLXDJPULJNOGVZFMYIRBFIEESIEJDBLYPARQERLKUEHYUGJIRKVQEFZLQUQXSKRNBZURWPLZSTPXISSJLUFZSMFXZIVESRSKEDNJEPGVPUBHLGWTKISYYJVQHXPHJDWDWQMAQWTZIBKCHEAETDYBJETTGZYHUURVERLLSCKUHSJMOAXTRYGKDXGISNNAHVQTEZKRKWAMMHAJGEJZOWZNEIZLZSSGLDGHXNEJPUBPPXNLJCKBFYDGXUPXITFATASDFNSHKWNZMQGXBBOSHEWBOWWCFKDCWVKWOTKMNEGJNOPURJJWAFPQOLNGBMAUCITMGZBOQIEUJEIOSNSMYQJTGVPFGXWCCCKDRRVDIHDYCTQHESHCTUUSSVQWMWTAOKIJALBPMGBEXZQFRIKAQVWBUXUNKBYMYSEXBNZHFHUSFGSKRQYZVKTALOHBMXSGHRUDUYSSMWFMPMMWFXCPISMWXIFEQSWTQQKUMZGOANSOASHGJBEKWLJBXENHHBWQQUCRQYNAATEWLTESGXPCWYFVQGGXTTPIBWSYRXBQGDXJMZFQRYDPKFPNYRQEFGFSZBGZRDVLHSYXTRTXFOIQIYBPFEXQDXBEPJNDPPBICIRTBBTLQUALXYUWPUDBVMJSOJPNEGIWXGCBFDZZSKWNAUIAXOVJJWULADOMBTGOTCIAYLIAGYTVVBZVVMYBWAJYQYCTNHUXYINPLAEIJCECYYBFIMUXXDGRKJADAFWWQKVSKLWKGPJPFZDCWNIHLERAIXHDIIIMDQPFTZVZTWYXYCUOCFFEYPBZRTSCPUQMWXGZVYCKTEVNJPBDUBXIUSUOOGGYGRTGAZTYRCGBKJFGXBRMDQGZXIGZDJCHWFORQKJJGUJTRIGIKOBYSRTIOUIAZWVHAWISDDWTICHGVEHSUTDFTGBIJUMXLNHLVXBOFPCEUOWQRDIELVYBAOAWLRCBJVKJCXYPJPGIJGNGJYUVFDNDCDBQXQMRYLIHDKYQHGBWBZOAOXPMALQZEWAAHGMSLSROAJPLGSIKFUSYRDJPQCOOQJTJVNPLIHJECIFUHIIEZYMJCQTCKUHSCJMUVDEZIMFEGOMRHVUVIVGMBERRPLGKWWOPLKRQIWJRZBYOSXROTLBUDGLWGKKWANWWIWJNQDCVOBSIPNXJEHKNUHSXCXDCCRSNBYZVXBUOAETHRQYYVQGLXWBWXYDRBFSBCNOSJHGTNSCIAXPCLOACAQGCBTXZGTCIDNGLAZCWXIFWKDYJWBKXDEUJZPQRLWASIKLSLFMERFKPXQYQFIRYHHUXSCWVLQZGSMLZUYOAFCUHMJIVDOEBHDKZYUDADMCHXQYIKUMKAPRPWSGDMNAGCSOOVPSCSWCENPBOCCJQXPBBDEHHVUVTFSLHGTKHASWGOUUQEDZYJOXUXELQAMKVNGAAJXMAHKARSLPRZGTDBKPRCXYHWWHWRRXXPRFKMJJNEYGHTMWCTNBQRCUAJPPPLPNJETEYDBRMLEIKLKGLJMUBPRLWIFEOOQCBGNOVMLMTZGYCGMSLCTKBVHJGUZLGYUJYXONOPRHMJEAHICJRUXILJAGNHHJXSLJTVMGGRNVKTDOJVHHXWZVJIEJCPPVKAVHWPCNBZTIMNVYGAKBJIGBNMLRAYUAHKJWCOISZHMGONXQAXWJZVQOGQUGAKJEXUNLTCDYRQWDGGOUUUUHWPRASTBFMSYGROSNLXLENLVETJKKSOLSMHVEUQRLJUDAMKJLWECCIHTUSPPTVXUVZZVDUVPVWNQUPLIHVDPUQVUIIGIYCFUANGHNOWQMSOQOMHLQNIKVQBGOQHHZFVCLPIYOXHIAXDLRZJGXAIJYNLVXEIAAIZXCUITPLABHDPJYZEOACHCRYUZNYNHPJPOPPGEKXJAAZLGPXJSNHNSQSPJRXZGYGSNDUWNJCQNPLJJGKIBUXGSPGUXZAWHYBWCDSQPWVTBCVDQRDXMXBMDVRXLPHGUFSTQPXOLOFIZKFDLJSUUUXCINQOYFULWDNUZCRJIOSRMOWVMMHNYNFBUKYXEFLIPBFEDPFJGHFXQYVUZBUNUJDLSWYREVCKMVQQVAATSRNUOSNABSMXRFVVMVTXITIYWUKTCDNZPYUGPPQOQRPDFMVUXMTKNZQWOJHWELRFYDFKTBGVVSZNBTDNPBFHAKKUFHZVUXRARYEKWUCYQXLIWONVNBYXNAQZBTVGWIDGTAWFBRMRVVKYAXJOTYYSQXZAJEOWWCOJXLBWSXGODJSUEOMYXHPUEPDYLWYJNDISRWYYFAGYMVSXPTGTTVWTFBSTFMFCYRLFISMGKAZVQBSNISILDCSLUGVWBBKWAXOPTHPJQFBTONDUMCCNEDSRBYOCIAMTLBAVESZQEAHGNFADENFWGWIGAQTOCSNXNSZNEVJMHVENBGUOOMMGCBGJBCPQPYMBHDKJPQDBLAMLLSGUEEFLNGNZJFQFZKONNDHXIUJDMBUNOVWSFBBJWRHIJSTMSQNSFPDJAXRARKGEDQDHWGZQWZRWPLWAUPUIGUXPAXHIKPDJLCQOMHRYRLJYOCSNAWRNCHSXHJTKNGMHYOHRFIYQJFSPJOMYBUPHUQJRWNQEESRWPGJKHZRNDZBQIQBNFSIAVIBDEWWSDRATKVZPBTTHJYASFTUCIIHZQTXEOTLJSVTZQWALTTBGQLPFSYITRVWMKCJOZWONQSZTPDLXESINYENYTAZYPVZPDBYGFDGEZTJPZVZDHTRKOTGZELUGEWSMYZFOSQEZNNSCVKWXCKBDDRMWFWUBJJHTVQVPARGEFMXCCKQLCOABKJYOKUPJYQNMKNDBNROJDPUANZUTBZRKPCOFJHKHJQWQZMNFOLTJVODPWFPJOEYBLPIOIWFQOETPAAZEHMYSNMSSFSTIWOZRTGGXHDKJPOKCDUCFOZJNQAUUZJONRAOJHVPQDMUHNFRBHECDFCAOLXXQBDEPIZWQHMONFDLDQDAHAZRHGJTXVUPDPZVNHJHSGBPMVFVAHYUYKRPQVSTNSQXEBMSSKJBYQKBXWSNAQZJSYPQDCRFORMTTBVWUBPYIXLLMZEOMAELSCBIMRASXWFFFFZDHEUDIRZKJMNNENEARMVLNGYGJMCAOWYICCTRIQUJAWWLAPFTBJGHHEHBVQJNIDKAGMPOLTZIKEEBQTQHFVDIAHJEZMIFWPMXTEHJQKGMHMMYPYQCARDOZERLTHGYWWJJEILSYLISWVPRSCIUXVXKSQWLKTRCWUURCLGXYQQXWQVOWXTLURZIKQRJXTPNWRNQAYMIMMUXCTZREGGHFXMMAAHZZMQIEQGBHORJGAAZAJNZIDKKXZIRRTUASAEOBPBWYDUCUILWFEUMSBCPWWMNDCEFNSDJBGVDYUOUPPLEMTQLOLVXLPFNMYNCTSSIJRLQDOWSUEREYCVPKJVBTAVKEANLCJVZHRUIOEWBCUYDLEYYDLYEYYMOUTROZIGJRHRNLISBLUGUNLZZLNHIWTDNGRLAVPOLOYSMTTLLPKDLQWNSXMIDXBHAXYEMRPYONJVJLYPFLMLOSLWTRMSHLYMSRJHXKXRGWGAIXBUCWRXCGEUWYUIUSQQPWKMHHSBDFSYZKOSQZXXAVXXXJKFCNIGXEQZNBBKEKCQOWQGQHTUIPEYUFJARTKKFHDOUHLHUZZFXLWHIOOIGKNPAXEXDNWIUQSOSBHDEQLKPLIRUQMUBHSQIGUNJSBWHLBFSUOTNJZWQDDXETAQNDYADEIGPJEBVGIDGLVDMIECXNUIELRZAUFRBSMNPOGJHHCDAVVKIYEOWLLAVCUZOCBDKPAPCUVHWXUQSUASGIBQAOROBZLGTAMIHSHOWXPQBVFCOSNQLMFGEZAZRXTIHWDWXATHYUAIDPSGBPUIVVROEXXUHHVCCCMNXFGAQIJNNVZHBEWULPGLYJHLRBFGPPJCAIAFKALYQDWBFGDYRCOQGXZLVLSMMDXEKDCMQIQBQVRGVHTYUZTHGATYRZVIGUMKADPIGSIFJZCKKJHEONIKRXKOPXAGMWBMHVPVPDWRADGMTVERKRWSSVLVFIJGMUBZTRSPNGDLFRBXGMHNEOJCMPFOAPWEPLGRABYLLXDLTERRBKDBVYGQNDYYNCHLWDWWYLLVQBOVIHFJLFVTMKDVINYKKERJKSCZTZEKQSFOSMPNVGSNQSQNDAVQJNNLQHJLBTXPZBXFYRRACYWMCKFORKWGNJCLFIXCIQSPWUWTRLJSICZVKZDAIQTURXNBGDLIREHDLDUCDNDXNSHRCLQLATVPHOZRTIXXIQYEJSARNKOOYIIFVLEGISMMEQNCMAKQLXRQRNEKMGFLCNCJWCTRDMEIFCZVJGTLGWDSTBSEUKVWEIHOHMSZKXUCCVHACKLKQJQSXKUJXPTSHKYRMUADWABQSVKIPFRPTDASYVGJXXMSHFNGRDXIQFGCUGHLKOWXPJETKDWUZHZFKEDYTKZEUUQDIJMWKYUVDYZPTWSHNJDBLZMNOTKGCWFRASJBPQYPTAKPDBFPFLZCEPKPTHTQAQVMMFXUUNEGOJOYRCSBIZZPEREIYMQYMBJIDTYCJAJVIQGHLHVYVLFXRJJWEJJEGVJOYCBVQEVXKEDKLRFSOMXWEKBCHEMLCIVTZXXTJOXHPZAIMBTJBHVSOGNWZBRFABAINEEBPWNYSBENBURPTRCAYWKCQCNZXWKRWVLVTHJWSOBEWANCJSLRWZOBPNITSTYNTVJJZNCNSPCFDQQNAMMQPVPQWTBPSAMWZECDXXCKBBEQKSKLALCZRZCNFDYOXEAYHHKRNF';

for ( var n = 0; n < 64; i += 1) {
    for ( var i = n; i < 124*64;  i += 64) {
        //console.log(haystack[i]);
        var vertical = vertical + i;
    }
}

console.log(vertical);

但是什么？我已经对这个大字符串做了其他（indexOf）操作，同样大的数组和性能也很好。这个嵌套for循环是一件令人讨厌的工作吗？我该怎么写呢？

Answer 1

这与字符串无关，你甚至都没有访问它。

你搞砸了你的索引变量，循环永远不会终止。在任何地方你都没有尝试增加n，所以它永远位于0。

Answer 2

第一行你有'我'而不是'n'。这意味着你永远不会离开外循环。

for ( var n = 0; n < 64; n += 1) {}

node.js：嵌套for循环，字符串操作性能令人沮丧

2 个答案: