387. First Unique Character in a String

Author: maxvoronov

README.md

@@ -1,6 +1,6 @@
 # LeetCode
 
-![Problems Solved](https://img.shields.io/badge/Problems%20Solved-32%20%2F%203031-1f425f?logo=leetcode)
+![Problems Solved](https://img.shields.io/badge/Problems%20Solved-33%20%2F%203031-1f425f?logo=leetcode)
 ![Language: Golang](https://img.shields.io/badge/language-Golang-00ADD8?logo=go)
 ![Language: Rust](https://img.shields.io/badge/language-Rust-00ADD8?logo=rust)
 ![Language: Bash](https://img.shields.io/badge/language-Bash-00ADD8?logo=gnubash&logoColor=f5f5f5)
@@ -35,6 +35,7 @@
 |  283 | [Move Zeroes](https://leetcode.com/problems/move-zeroes/)                                                                             | [Go](go/0283_move_zeroes)                                                       |     🟢     |             Array, Pointer             |
 |  344 | [Reverse String](https://leetcode.com/problems/reverse-string/)                                                                       | [Go](go/0344_reverse_string), [Rust](rust/_0344_reverse_string)                 |     🟢     |            String, Pointer             |
 |  380 | [Insert Delete GetRandom O(1)](https://leetcode.com/problems/insert-delete-getrandom-o1/)                                             | [Go](go/0380_insert_delete_getrandom_o1)                                        |     🟡     |  Array, Hash Table, Math, Randomized   |
+|  387 | [First Unique Character in a String](https://leetcode.com/problems/first-unique-character-in-a-string/)                               | [Go](go/0387_first_unique_character)                                            |     🟢     |  Hash Table, String, Counting, Queue   |
 |  404 | [Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/)                                                               | [Go](go/0404_sum_of_left_leaves)                                                |     🟢     |      Tree, BFS, DFS, Binary Tree       |
 |  540 | [Single Element in a Sorted Array](https://leetcode.com/problems/single-element-in-a-sorted-array/)                                   | [Rust](rust/_0540_single_elem_in_array)                                         |     🟡     |          Array, Binary Search          |
 |  704 | [Binary Search](https://leetcode.com/problems/binary-search/)                                                                         | [Go](go/0704_binary_search), [Rust](rust/_0704_binary_search)                   |     🟢     |          Array, Binary Search          |

go/0387_first_unique_character/solution.go

@@ -0,0 +1,46 @@
+package first_unique_character
+
+// Use simple array of structs
+func firstUniqChar(s string) int {
+	const alphabetLen = 26
+	type freqData struct {
+		amount, firstIdx int
+	}
+
+	var charsFreq [alphabetLen]freqData
+
+	for idx := 0; idx < len(s); idx++ {
+		data := &charsFreq[s[idx]-'a']
+		if data.firstIdx == 0 {
+			data.firstIdx = idx
+		}
+		data.amount++
+	}
+
+	for idx := 0; idx < len(s); idx++ {
+		data := &charsFreq[s[idx]-'a']
+		if data.amount == 1 {
+			return data.firstIdx
+		}
+	}
+
+	return -1
+}
+
+// Use maps
+func firstUniqCharMaps(s string) int {
+	const alphabetLen = 26
+	charsFreq := make(map[byte]uint32, alphabetLen)
+
+	for i := 0; i < len(s); i++ {
+		charsFreq[s[i]]++
+	}
+
+	for i := 0; i < len(s); i++ {
+		if charsFreq[s[i]] == 1 {
+			return i
+		}
+	}
+
+	return -1
+}

go/0387_first_unique_character/solution_test.go

@@ -0,0 +1,60 @@
+package first_unique_character
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+var testCases = []struct {
+	input string
+	want  int
+}{
+	{input: "leetcode", want: 0},
+	{input: "loveleetcode", want: 2},
+	{input: "aabb", want: -1},
+	{input: "acabbc", want: -1},
+	{input: "a", want: 0},
+	{
+		input: "uindrseqbljlhqvlwvgdebeihttirikuahlikgnahvgnptmqwbovmuwesxkvcitcwrwrucsbbfqvldridfviduqvmfcmeiphoqupbitnwdbvevouoaetisdmgvvvwoglwtgjrpcbghxkrkjthetxeexbphbjiehaicuicgnirslhdstgmqcdnlulpdpadjdltfouwhfqicfcqntnpeqaohslwkhbvflxaudembsrsindluthxapnmrqinsivbxmkohubvmmmpmklbfrmeuvdrhptdmelmjjefgbsqqlbqhvsmswwxrlkutadqbbeisbgfrcivvoxmxxptrscxnjjvtajfhqiucdihihcutxhlonlomfdnbwanrcnbarojsajseqrgkuqgkcnvrghxnmbclfomktwfaakodeecsglufvobkgoqsbrhdiuhxqbcndkmxuertupngvnkgwrfwgdbiurbooxariklwarjgavsuddoveipltessrssxwxgvrrtkisnbavkbpaphicxhapjjpkccakepuafjdaswfwfmbdmuuaveukxvnpkgmhcjcpqntssthjlvrngugbhrivtwmbrvrprrlfmvwjdkonfmgnepqoxwfcvefjihisarwskjfmqrjlkbbugfawmkqgfxgpokkxxivqbqimwsccdekjegwcxhmmuhpstxfpofwmrmhrxeptxwbvxsesheijjfsshgrrwckjkmbslpbngnwhokjnujtiepfrdhiwwgbffixaidabacaibummwxgxowsewlqfxrkarjrkqxmxwobqbcoowmbggtpoqadhqdxlhvxrkfuwpxxgnchudreoeuefkqhlrmwwfvjexvbxdhtdngwvoohpjtdbdbesceiafrhenfljleegsencfmbauxlltfueudnjxsiiggsfwiuidgktsbtcvxtdllviocfdbonjciosucbjidwxnogmnveqkcrxbpamfxwxiugjgrfpstromuxxdiodqeoqdlfulttraquskhwfholbrcbchijlgqvuwxvejedikvgetlmrcmeampdgjvmbdovkcjilbralhmniwvbeandldnudkpjvhoqtfdwllridwljfvflfdrbqadvabggwsiexrthrngexpebuhtefkqgkkjoopsmunesfotsprxuaswwenhkdvsspkppulecahkkvccqngeaoijjgvsfqfpvphvhdnkkcqsebhijkvfpqjmarbkpejagtbtisnflrrvawmvfxeccxtrmorihgslxlqrqcmouojjfhcieuwlrcqhevmveookgonxqdbtgqjimsidnaaiuchwkfkpxfptuvhfqemojixqvhgokdekdwbomptqqlfiaiptxvgfmovdqxupjxjpoxuplsagxpgpmvtcpawkrrthvclhdbpqeucchxptdceswhnqocmeocpgthkgxmxggwlnantwwuoqpmnpvgateitxlocmhnihmfgjnvrggenbhnjfubtoteojojjkjpcnwqthxhlfukingjletwnxdnjwrgjopqoxtqcvwsakqxxumbtcblufdmdvxfkshitenmenkxjvblsoiyhjpakinimwxhcebabgsvqftfvwjnstltjawhwipkubadtoxqrutkwxjnmfoowtnvqplvqokcuwlkmxxhboampcdwokjfxggtnojebagxlwaeowtomubtbfsrufkttugfpnxmipkcsphqafjuxovwpcgonhiqmomsweunoeqkpkxxsdksmufowqpmkontccckcdbwrfwamikananakgjkahndrepemcgxecgpltvdbpoexemnrejdephuuxhfcubxlbdrmhvmeqmtdhnbkwnidigxdantmkckijiecavkpumegrbveffclcltmibjcstrrauphfxxssgxkkirapiihnlbrodvfostahqdkajqtrrfwdsemwxlucbbjjspnnqjnpnpmimhulgoskwpsactexmkfdhaihnlggqeunqevxfrpiwskhrhgfluelshqejavomjshfomvgpugqesbtakvxqwrtguuebcgqphocglfrircfvuikfbviomfrsnpvvlftwrkbmjpvdpgvohtmxcxwnuhwojnfvsfwvdlaxxlmafihpussffcawjpaxdwerwfbvsbipljualcnhseealvqiqfiaiskaafufaubvhjglktfhbdsaskmedroxkrxshnggumcbtdcablawkodmnafkjekuiecqlvbxocfcwipaicgndfafjhtjcelakrecmntjxeqjqgxkxapuobbcaxfrpsktjswxdfvugmmgjwiphnsclqwmranthpiueffaxvhplajqsrtoxbixbdpcfkbpkjkelemubwachcpxcniaqmkmasmvlfcubcdkxfkupgcgbrvmbmgnjgfbawmmdritdrkppswatwtdjemhifhmshunkvaivhteqnwkdcrpfxmrafupfhbgligbvrqjkvcgbiqudvtblhfgetffduvsfhsmjimgruxrvbqniluapaoniwhqhltbxvrphmlisfaomqoecmdbbrgujgsbdelkbddcgmpggogfonssxisphbwljlvhwhewmpqugxgbubqfeilobxxhtcxmxvjtbuavxlaghhjiemihvrsjxbleutpuumgndtnocwkpkdaupbmcsahcbwoelmgnwqummmekwhpahtdvehoprfcciwqphfwppscruimikiximhbkdomovbdalsihioncpaclevxawqcqthtmuogolkrvlipropmnmecttmlecpapdlrcqxopfjobgsvhcadqiudqjoscpvjguddnorldkpqtoocrtkcutkvdpbkkekenpqjmxmuxccamkwwxrdrbdmameptvcgsltqdasicoouvdtbranexokmtkioptqblrruaihvfvvebjigkuwwgearxvmimlgmxgpvbnotepprknjxcunheclsvxxmmoufvdhrwxqlrkmvcaxtbiqrjrnrsfrkvttnpxbspnetcofhpcbcphrchivnrskkalsvdllhtisnaerxbcxutcpmnquwrutmmvrtchhheplhdmbfkrrrxalosjbebtdqtsjbdcuuatgldnubigijbkehxsmhsadwtcbwinlnilthiqslvsduspkjuunpetcofujbqhtkmalnjmllhulckqodbgffxdiqjajecbmlekvepkirxnguqnpnfjdptinuphcoxkoqhqrmkkawmngqwvfpcuxgpekkprupplsbwshmsduaitlhcjargacduewtqgnxbtpwrkawpncarxlsnardkftmsdjflmhoplghandjisupacixxthwokctbxekqwbmhtoutgrogxsdnmcaqrsqrpigbigqhsmrksxgkdbdbxkwimpehltcffuhrphbaqgvabjduudbrxgwiljkwijvaugnleamskjijhnvcspagsfnhjielrvxddxqfgaipfflffksmvgaioaclfsjhovcotoaiwhhnmrudsqmsepsgdofnxjjcgdejutmdtgauuvuepajlikebtpgfimudswplfwgaodtwqjuaujlbqqartevsqesmrpknoanfprqcwochqdrcvquovtsogptduvfiaislfvpxwsqitodxwckprpfxtqhbdixklhtsajqgbinfpdqaehrwhnwggmggnbstolrcbmlhpfjurbknpwbrfhvdanrjcwnvsxudagbkhdlwujqvwpbbgmsfrkgutkqwxqfemaaokrfdocsbbktwaugoadgvqcdhmqkworbvxqwdpmbjkqghmapevrsnaaparwnbvcfnhhgfqplfwiswrxxistamulcbxcmvkbcxsgftbmbvqlxrhbmcujkktdvcgnjkfaclxndtjkdbgqvbqxicgmpowbjsfvspvxtrovjwbbkaapfgcqbifdosnmutvfbgdmhiqvflasedhafqnmrlmwbuhmptnkvvojnjngiepmdktewwsuxernpfmktsgwwnxfvmuotpfxfntcrsjpldmringfpkpievvbgbghevlmuticukrfvahrmtkvckjbxxrmkilbeojsxgbvbhsgvkhgtjddoreipbkwiqbkecobfexswiwttlohnfwokixfmfrpadtudrssiobbvhctpbeesiogwhdqojoalxpxikwuheilvsrxbfbnckjeswhkfviihvwrfxkxcomhvsjojhltospooumkstqqnvxmrowlrtufhxkipxnfecchklrqljfwnglxeharemawsbvnuentnapewjhnzbieisjtomdqtjkigisgopmgcfqxcxninrisupchhmfrosxgdtakhrrnbbnxovvbfjgwdgnlxoxswhsfjeijvivqemoekkmrttscthlpglaorarhibrucuhikfkphqmhowloobeumlikqmmlatesupiekwjhdvntnjbakohrbobimmujkbatfxpmgfmmqsgwsffcbenwgdrhlqrsmfghevnjfdlxupihmkptsefubmixhacnxngpjrckxhvhrelolqwevoqklhxbplakmsxdetvpuddmvaodpglmsknbvfftstckjurbntwqenuhcurxqvotrxfpootqkobeatoduihwhpjxxrvboggkcxagnrrfwfuaqplirlnafprumnkcjxlpvanfmqwuoaupqptqeulpwvnhbahbkihustenkbdushjakemufdhjllnowmvgpdxbrhxfonpgcjslvwgdmajicqqmdxubrofvdodfsedjghpbjncgkckeudxwascljlraoodwvgpvojcqgbalntslsfrwnfcdvidsdrvwhscskpalubxeobapkgpdsqcjpwkednraijmbcreplwijofniggavpdlwfmwnvsaridhbppeolakquhamneffnfmbruivassdaaikxiaxupgdpgkfojvkkagcsmqnweofwikvevrsottkbtcldoruakajinnlgxmpddcrmohaktsdrxjelrbmfdthspikxeocqqdordrqwjtaxihswcubtfomksaxddcvtadnrtqkmdnacgduudtdbhsgpfomrdiaotcfwqlxccqeelgtnkflgixpjcriroruhbbgpidwkggdevpfratqebewaxcudseaikqjuuhpsguvtwxniofskkslfnrphatmxngneuituefcxufisrsjitqxwufrgidbwlmkrqojpwpljasaiukwwthrudhcocoguerakhajdncxbrnuavoqeuwsamwdqgutbaoixcgeibpoajhedooqcewiqvddedmanxljjjcbojgbmwabkfbvamgnfpncdcxoaqhmgurifpwpgrpctlqpwmqraknjltneknsphtwbnbiahknxipsovljkivlpggvldeveeopvoqlvfjbratadttlcecomllpkdgiloeedquivsnmxkfcvrkwaohgbrbvjklkktgwtlfgafqgbigheajrvffvvkkmibcedfmnwasopoqgxjohjoqnijeaifuwiwmogkwqlfmibuwecvnulvhkbsukscqlqlsxjulillmlgjkrbmllcunhbqmbujftqgkpwkvemthigednfohxpsduotwfnknfjbexflcfieaosnlhndsorbkcdlahovwbccshmrlcofowrmqajluiqaarnqtxokbaddswftiexiahmstpbonwmhvqgcpmfrocvtwfhjrtsupscfmvwfvaoolanrlgdsvgoseltdnoxrdglockhwlvffaakgrxjfnfbxnbprfvpwmexnhfekjnkenbohhmwlqoteiwgtjsrnceptbgwkfcmtkliwwqskmsoihmnbjsvnmfkwbwemijdtpnajgrousbrdaagenqlgeaiixfgcbfhceaxkwxbpksfouuqcvcerqecpdtvtsubbadmaatdnmnqhladeiapejkxffoagbwqbvppssvvvhlvhntatxlvqgjxbejpvxemqbdjknuogumrwbognklmvjsldrktpeowiuaapbjgktxwfjiferxgmafbcerteqlvpqvxbgdwiufdctkwptadtujmifppudubpmdtiedmqhnihquansnjufpbuumhhmidphkwusjdsdaocavtauhsvtgcoqhufmacwcbxvjmagkounkoqpcnoanhgwsjvgtlwgvbpdbufekosgagfsmadmvbonkrtcbspoabugkcjeebqhqwfjcqlqjvabaqecofgwskqplgup",
+		want:  1615,
+	},
+}
+
+func Test_countGoodSubstrings(t *testing.T) {
+	for i, tc := range testCases {
+		got := firstUniqChar(tc.input)
+		if !reflect.DeepEqual(tc.want, got) {
+			t.Fatalf("Case #%d: expected: %v, got: %v", i+1, tc.want, got)
+		}
+	}
+}
+
+func Test_countGoodSubstringsMaps(t *testing.T) {
+	for i, tc := range testCases {
+		got := firstUniqCharMaps(tc.input)
+		if !reflect.DeepEqual(tc.want, got) {
+			t.Fatalf("Case #%d: expected: %v, got: %v", i+1, tc.want, got)
+		}
+	}
+}
+
+func Benchmark_countGoodSubstrings(b *testing.B) {
+	for i, bc := range testCases {
+		b.Run(fmt.Sprintf("Case_%d", i), func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				firstUniqChar(bc.input)
+			}
+		})
+	}
+}
+
+func Benchmark_countGoodSubstringsMaps(b *testing.B) {
+	for i, bc := range testCases {
+		b.Run(fmt.Sprintf("Case_%d", i), func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				firstUniqCharMaps(bc.input)
+			}
+		})
+	}
+}