LeetCode之Find Common Characters（

问题：
Given an array A of strings made only from lowercase letters, return a list of all characters that show up in all strings within the list (including duplicates). For example, if a character occurs 3 times in all strings but not 4 times, you need to include that character three times in the final answer.
You may return the answer in any order.

Example 1:

Input: ["bella","label","roller"]
Output: ["e","l","l"]
Example 2:

Input: ["cool","lock","cook"]
Output: ["c","o"]
 

Note:

1 <= A.length <= 100
1 <= A[i].length <= 100
A[i][j] is a lowercase letter

方法：
统计每个字符串中26个英文字母出现的次数，然后取出现次数的最小值，该最小值即为每个字母重复的个数，实现原理参考下面的代码。

具体实现：

class FindCommonCharacters {
    fun commonChars(A: Array<String>): List<String> {
        val letters = Array(A.size, { Array('z' - 'Z', { 0 }) })
        val result = mutableListOf<String>()
        for ((index, str) in A.withIndex()) {
            for (ch in str) {
                letters[index][ch - 'a']++
            }
        }
        for (j in letters[0].indices) {
            var min = Int.MAX_VALUE
            for (i in letters.indices) {
                if (letters[i][j] < min) {
                    min = letters[i][j]
                }
            }
            for (index in 0 until min) {
                result.add(('a' + j).toString())
            }
        }
        return result
    }
}

fun main(args: Array<String>) {
    val input = arrayOf("cxizlxaeicvxwiaqebzdzjfqmtjtrbnrehrisntpsmsntpsndsvjthgnubvekkxqwzknqqrcutenoeseqakkldnktsqpbhkklazy","zohpatikncppgxcjpzazcwjaqbhuaokxabfvfrrbyvgjimfujzvsebjbvegwgapdixvzblrkqpzrdbtxlpultojuhwzqetvplpdf","vutkluptjbjaahtaweadgtcvasaujlwgqrufojtakworsxlzlkkatwrnqxmtfbcmfjbbnpyitirnnvtmtlqxfzalycigeeeqtaqu","intoasbpbflhukiroofoqzpeksolynoytjfbcmeoeamxxbnlfgdwjwpenhufllcrnjrxttbevqdxqmxyvvguuliqfvbdalpkbawy","zizxutlyzcwwklwndwmgnquzfwaodungcpkhudujtfgcfpgsaatsflcxafskssjxhjhwexxgiwefozusudcxuwkroogopgcsjzgl","lyesyttpoqgrplyxzpqqajqqafygvyuzkxwggpmpuvrlkgdzowyhhxjopcxtanieccgwzursvnvguwikgyszbybqthewgouzerpz","msfudeekbpluzevvypmamrqhrdmjqclqsteprmpszzoigjuzrcofmtrasaokotykharcpddjufoufzoifrqlfpsfdemnptjxlaxv","qcarngpdtsuakowbmkgnwmfjmjwmxkxeqpxyhcjnsrskuequgqlwppwwcgisepfnbxirpgynyymdqbzrbvmwupsvzdmylccylxkm","opwvbicxbdcovfrlhxmqhytujlknkxazqooghibtajaojhssbbajzcqlyacbespfluawhygjwkfowcueylpogablbmmuhdkewhpv","fuutvjfdwhhndlxuqxulutzepevejifzvkudvqqvkxhpkfixtrgugzyminanprvguibaocheuxqxhvxibyqjsomjdvnvxezmsorp","myhbmytkraqvtvgygpmscwcqqtkzbhyyggprhovjpjyqijdrgunyxymksocskvurczbsmdelbusuqdpofskzamhklmhrrgdjqtge","ynwjqmhdsstcahzioqwnlftajrnbhdembeitsczfqoztjhfaxkpojhawgtsokgzzjfyonkcsisvxqodducsnhgkclvgnyrbbfkuy","qgigwnrfatzcrnrhvnczfnlcjratbkbcvnegnodqqbyuzghsbmieamvwqqlrkidicnmkjrlohjtrgkbitnpxzwsxqzbdidzaveyx","bmfvderczfvirbashmriyzfrkwceebvwhpyjnlahoyzcuitkcezpnavgloycjxjaqrasckgfkwakplyyjkbzcdbhbrehwpjihngy","ykcazotwzfalckzeyjxujrkvukxsjuxgilopctogqmrnvzhpsnseadhifhhjloawubvmiqvyzmynrvisnyjupjwgfzdhctrgmiov","pukyolrguitgcnzddpwwpqxemttsujduonbjovqngzpbaifivisqojqztcyblerocqottjayafypdzzyvymlkrdihcvjqpawouiy","ejuejeqynodrspsndrmpjkcixvjxogoprzjgyxnsctcovaubwbkqaajtfjvcmrnrkcmvspvnwesitvvnimezjcgyrjimcwnetmll","xujtbtnnacezhqbzrpelbgbsnmwvuamfbvxxjjkcynsojrhlebzeptnloqgyxlfdnqcdwxfxazaxcmxkcrneiqheycgvsbgltvid","qldmyynkbixpfjsdvlgfngzrhdijjxeehzebaquekjfpxofxvugnftclfcczvoqigfkievyvormswqpwvqbnobvhqjadiavgdqzw","bncxmbpwuywvnaeecphfwvbpuvvknxkzsfeykeaejdrcitwtioyenzxjfsiagbsunnokmjclaffcoozgayuhjiypcmeijghndzjn","rerjcjeqjvdyzzyybnbwzheozqrvjbjegzfvgwuepexsaimjtfcghoaxdsdlltahlkzneuevgnackjoohginvpqcbjxbexbqfgyc","vgsskznernyntiwofhoqkntgeclhhgoyihgeeodumqnwxwrhqmgnhlubftwjwoijfymfwugxqsxwsytjctuqcxcxuhlzcllhyfri","lgzsgpurzxthlzehntsvkycdavippybpnkbxjpkzdlkyxffllbydeziobquhotpbshtsoeuyoutytdyduoadxeancbnysuxzorad","zjfekgidfvzzbhzoksizpcylqigaacvgqcgmzntxzrtmbucnmmrgbkbexuunvyqqnbrgnottufxpylvkbmqdocstubrfgwuqkdcn","trlgbgboeszlfgadqoxwpjtkwpcrnticpxgdgyxmibjdhzrvkqzajqjhozzkiqffnwcqyuexdselwfumyyvvamiizwvztgimzgbp","mlimwoskddyxunxgssfjgfcdrzbswtiyqdyamnikfhfdvfbhnltkgatdttxprfgafnufaqpzbdgmbnogesvuysqseuckbqcmpzdl","nvlxantvgwrtmzzvutdjvsfftnjthfferdhejcfmhvvhunxzsijvyfigonnfrdzflvbsxnftjfxfczxoayrkouwycwvmhsfhfmyt","oijzdasbaiylwkvqqmbklzbmajydkpwaglivwqqhvljvjxglkslutxjrivdgpazioaiaoobikvxlfjmizipgkhvughuoxowykuqr","epyfwunrkauzbbsvuaoflozsaavyjkcuusjndiyqeatigykkbvoihfpuljqdjckemlslgdfkvmydateenrvzhavtsjrqobvvyaqo","xxkfwqdzwffllyqczpnkulqzuokoogssiqyzaxehyomsgvaxzqnzflzwzzavnmibtzddwrlnuzljtojecrbbjucgyijjyinwozrj","ywpjlyfbwsiognlmkszyzpxcglnlacldfjcuziemxtdeepbwewwlxfqquomlsfieomdmsiqavuqrftydpomufvewlbqvlojdmgfg","xkceantgnjkiybxcvplnpxwimnprwbtwasjquwmqkrakctprjmnfdpsqjlwxuzwykuchddgsdlccgyqpolckeecgfvejderxtngo","lvutlzkxcevzpqszqgdayhnyllkgrvbimougbdmgbqdzwtrddgxkwqczegfnkigphwghsosruryztixvqgrxoziiubxwoehtqoun","pzorupuimoaxlyfrwweufewwucosqnrirupklqjekyktreaxgaxaqgncmwwkgwprybafuwtsagjyrawbpqeqztzdrmcpzhxcomjh","eyzcwioqzvcmtxvtxxulcnxwewewbpgjyzpgcouplsctjipuwiutxhdtczetfxnnkifkvwhiamxjjppaubbwxvqrmpymzvgoevlg","uasbblgcquaqcormaeupxgykzrjypwccgwbypsvxlnswbnwlixvjlzkirnlzzibkicrtlupwtoebxcemwvjkidvmlivouxiynnal","nasxfhzdreqnspwuourravhdbjchfulzvgquccvevbodabeievzgvzegubfipdeoaffrgnyjdzshvtiotmjieezilwwkqhqlivts","dimmqymdjhbsfkegyxfmejnczmfnmrajcxfuqymxexhmynyrxkjgpbdwmwdsckzcjymoasudsksobvebaefjngzvzqkplpoehfjh","sejxqwviqhlkbartmgwsvuwruemjqpaepilbyaerwjziyecmmmeothvosfvxcyiecjxkdxfqfnmmzahndoduzhutzuhfpuszcuhv","irhbaqsjmsjbwvnxhtqgocwhqqktfiquoveymoqlrussuizzmwipoudtlnrajonjmcmoqmvyqwbeznrqwrxkphozzplmnnwbygio","nrvzlftzhwwfeckjtoknipjpokzwnbacdauzfnvebpapoqpyseaeyzicfsaljevtkwgivtxfjrrmocsmvimctfvrboawndjjgumy","droxndceqfcpkqgmkrdeewtdxxmsgimnzsrzojkqwhavlzvpvmrtlttxhrtehcapcncxvfgxkpatabowpigzldstfbsiqwezvbww","uapczwtmobvrzurhsxkodzgouxoeffgerxtxkvyaghvtzqzshqgmrrtwxkfxsisdhonyvmescqxqiltaumknxycdkzdijwkaaotg","ijmsesoptcjvpducnyahcxsojqkrzjbcqwzzxfgacynhxknvkaosrnolagfiutvrwaqsxmrbofmduxrxxnxmxlaccxqzlbvrxjra","veksvbkqchdgnkneqdlslicomlnnceijpsmgtaehnzsvghfabvdiwzjgdecjxsdcestuemlobekumtaxssdgzftxvjjrnhhdyfzj","xtotdktrxgnvmqzxchalgdywlysribmxxjhgznotfjgtrxhilkrlsdofswlyflfzgxerykdgqdmxkyxjlopolafuznutdbzygzlx","eiehlrjgmquyephjgqlmpvnxzbownzdazsyspurryzqribvlzyjigcszsuhxgtyycfwlakzaixmqorrzejooqkmrdggmkghbkesj","ktataiirpttwjzyypfjsquylawvjnjtqpveynzftkxohlcwtprhvpohmrhhnhnjyjsgkgouiigliduyioqkaaavnyxpkabqehelc","gacnwampmavvepmrnztqvmggpxcnbcioicwtqgalidjuqmz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    val findCommonCharacters = FindCommonCharacters()
    CommonUtils.printArray(findCommonCharacters.commonChars(input).toTypedArray())
}

有问题随时沟通

具体代码实现可以参考Github