{"id":32096,"date":"2023-01-26T17:42:46","date_gmt":"2023-01-26T12:12:46","guid":{"rendered":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/"},"modified":"2023-01-26T17:42:46","modified_gmt":"2023-01-26T12:12:46","slug":"solved-sudoku-solution-checker-in-r-closed","status":"publish","type":"post","link":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/","title":{"rendered":"[Solved] Sudoku Solution Checker in R [closed]"},"content":{"rendered":"

[ad_1]
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Here is one. It uses the interesting property found here: https:\/\/math.stackexchange.com\/a\/157716<\/a><\/p>\n

check.solutions <- function(solutions) {\n   board <- matrix(1:81, 9, 9)\n   row.idx <- row(board)\n   col.idx <- col(board)\n   squ.idx <- (row.idx - 1L) %\/% 3L  + 1L + 3L * (col.idx - 1L) %\/% 3L\n   grp.mat <- t(cbind(sapply(1:9, `==`, row.idx),\n                      sapply(1:9, `==`, col.idx),\n                      sapply(1:9, `==`, squ.idx)))\n   flat.sol <- 2^(solutions - 1)\n   dim(flat.sol) <- c(81, dim(flat.sol)[3])\n   colSums(grp.mat %*% flat.sol == 511) == 27\n}\n<\/code><\/pre>\n
Quick check that it works. Here is a good solution:<\/p>\n
s1 <- matrix(c(9,4,6,1,7,3,8,2,5,\n               2,8,3,9,4,5,1,7,6,\n               5,7,1,8,2,6,9,4,3,\n               4,1,5,2,3,7,6,9,8,\n               8,3,9,4,6,1,7,5,2,\n               6,2,7,5,9,8,4,3,1,\n               3,6,4,7,1,2,5,8,9,\n               7,5,2,6,8,9,3,1,4,\n               1,9,8,3,5,4,2,6,7), 9, 9)\n<\/code><\/pre>\n
and a bad one:<\/p>\n
s2 <- s1\ns2[1:2] <- s2[2:1]\n<\/code><\/pre>\n
Then indeed:<\/p>\n
check.solutions(array(c(s1, s2), c(9,9,2)))\n# [1]  TRUE FALSE\n<\/code><\/pre>\n<\/p><\/div>\n
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            <\/span> <\/p><\/div>\n<\/div>\n
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solved Sudoku Solution Checker in R [closed] <\/p>\n","protected":false},"excerpt":{"rendered":"
[ad_1] Here is one. It uses the interesting property found here: https:\/\/math.stackexchange.com\/a\/157716 check.solutions <- function(solutions) { board <- matrix(1:81, 9, 9) row.idx <- row(board) col.idx <- col(board) squ.idx <- (row.idx – 1L) %\/% 3L + 1L + 3L * (col.idx – 1L) %\/% 3L grp.mat <- t(cbind(sapply(1:9, `==`, row.idx), sapply(1:9, `==`, col.idx), sapply(1:9, `==`, squ.idx))) … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[320],"tags":[321],"class_list":["post-32096","post","type-post","status-publish","format-standard","hentry","category-solved","tag-r"],"yoast_head":"\n[Solved] Sudoku Solution Checker in R [closed] - JassWeb<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"[Solved] Sudoku Solution Checker in R [closed] - JassWeb\" \/>\n<meta property=\"og:description\" content=\"[ad_1] Here is one. It uses the interesting property found here: https:\/\/math.stackexchange.com\/a\/157716 check.solutions <- function(solutions) { board <- matrix(1:81, 9, 9) row.idx <- row(board) col.idx <- col(board) squ.idx <- (row.idx - 1L) %\/% 3L + 1L + 3L * (col.idx - 1L) %\/% 3L grp.mat <- t(cbind(sapply(1:9, `==`, row.idx), sapply(1:9, `==`, col.idx), sapply(1:9, `==`, squ.idx))) ... Read more\" \/>\n<meta property=\"og:url\" content=\"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/\" \/>\n<meta property=\"og:site_name\" content=\"JassWeb\" \/>\n<meta property=\"article:published_time\" content=\"2023-01-26T12:12:46+00:00\" \/>\n<meta name=\"author\" content=\"Kirat\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Kirat\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/\"},\"author\":{\"name\":\"Kirat\",\"@id\":\"https:\/\/jassweb.com\/solved\/#\/schema\/person\/65c9c7b7958150c0dc8371fa35dd7c31\"},\"headline\":\"[Solved] Sudoku Solution Checker in R [closed]\",\"datePublished\":\"2023-01-26T12:12:46+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/\"},\"wordCount\":47,\"publisher\":{\"@id\":\"https:\/\/jassweb.com\/solved\/#organization\"},\"keywords\":[\"r\"],\"articleSection\":[\"Solved\"],\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/\",\"url\":\"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/\",\"name\":\"[Solved] Sudoku Solution Checker in R [closed] - JassWeb\",\"isPartOf\":{\"@id\":\"https:\/\/jassweb.com\/solved\/#website\"},\"datePublished\":\"2023-01-26T12:12:46+00:00\",\"breadcrumb\":{\"@id\":\"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/jassweb.com\/solved\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"[Solved] Sudoku Solution Checker in R [closed]\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/jassweb.com\/solved\/#website\",\"url\":\"https:\/\/jassweb.com\/solved\/\",\"name\":\"JassWeb\",\"description\":\"Build High-quality Websites\",\"publisher\":{\"@id\":\"https:\/\/jassweb.com\/solved\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/jassweb.com\/solved\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/jassweb.com\/solved\/#organization\",\"name\":\"Jass Web\",\"url\":\"https:\/\/jassweb.com\/solved\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/jassweb.com\/solved\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/jassweb.com\/wp-content\/uploads\/2021\/02\/jass-website-logo-1.png\",\"contentUrl\":\"https:\/\/jassweb.com\/wp-content\/uploads\/2021\/02\/jass-website-logo-1.png\",\"width\":693,\"height\":132,\"caption\":\"Jass Web\"},\"image\":{\"@id\":\"https:\/\/jassweb.com\/solved\/#\/schema\/logo\/image\/\"}},{\"@type\":\"Person\",\"@id\":\"https:\/\/jassweb.com\/solved\/#\/schema\/person\/65c9c7b7958150c0dc8371fa35dd7c31\",\"name\":\"Kirat\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/jassweb.com\/solved\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/jassweb.com\/solved\/wp-content\/litespeed\/avatar\/1261af3c9451399fa1336d28b98ea3bb.jpg?ver=1776403586\",\"contentUrl\":\"https:\/\/jassweb.com\/solved\/wp-content\/litespeed\/avatar\/1261af3c9451399fa1336d28b98ea3bb.jpg?ver=1776403586\",\"caption\":\"Kirat\"},\"sameAs\":[\"http:\/\/jassweb.com\"],\"url\":\"https:\/\/jassweb.com\/solved\/author\/jaspritsinghghumangmail-com\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"[Solved] Sudoku Solution Checker in R [closed] - JassWeb","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/","og_locale":"en_US","og_type":"article","og_title":"[Solved] Sudoku Solution Checker in R [closed] - JassWeb","og_description":"[ad_1] Here is one. It uses the interesting property found here: https:\/\/math.stackexchange.com\/a\/157716 check.solutions <- function(solutions) { board <- matrix(1:81, 9, 9) row.idx <- row(board) col.idx <- col(board) squ.idx <- (row.idx - 1L) %\/% 3L + 1L + 3L * (col.idx - 1L) %\/% 3L grp.mat <- t(cbind(sapply(1:9, `==`, row.idx), sapply(1:9, `==`, col.idx), sapply(1:9, `==`, squ.idx))) ... Read more","og_url":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/","og_site_name":"JassWeb","article_published_time":"2023-01-26T12:12:46+00:00","author":"Kirat","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Kirat","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/#article","isPartOf":{"@id":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/"},"author":{"name":"Kirat","@id":"https:\/\/jassweb.com\/solved\/#\/schema\/person\/65c9c7b7958150c0dc8371fa35dd7c31"},"headline":"[Solved] Sudoku Solution Checker in R [closed]","datePublished":"2023-01-26T12:12:46+00:00","mainEntityOfPage":{"@id":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/"},"wordCount":47,"publisher":{"@id":"https:\/\/jassweb.com\/solved\/#organization"},"keywords":["r"],"articleSection":["Solved"],"inLanguage":"en-US"},{"@type":"WebPage","@id":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/","url":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/","name":"[Solved] Sudoku Solution Checker in R [closed] - JassWeb","isPartOf":{"@id":"https:\/\/jassweb.com\/solved\/#website"},"datePublished":"2023-01-26T12:12:46+00:00","breadcrumb":{"@id":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/jassweb.com\/solved\/solved-sudoku-solution-checker-in-r-closed\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/jassweb.com\/solved\/"},{"@type":"ListItem","position":2,"name":"[Solved] Sudoku Solution Checker in R [closed]"}]},{"@type":"WebSite","@id":"https:\/\/jassweb.com\/solved\/#website","url":"https:\/\/jassweb.com\/solved\/","name":"JassWeb","description":"Build High-quality Websites","publisher":{"@id":"https:\/\/jassweb.com\/solved\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/jassweb.com\/solved\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/jassweb.com\/solved\/#organization","name":"Jass Web","url":"https:\/\/jassweb.com\/solved\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/jassweb.com\/solved\/#\/schema\/logo\/image\/","url":"https:\/\/jassweb.com\/wp-content\/uploads\/2021\/02\/jass-website-logo-1.png","contentUrl":"https:\/\/jassweb.com\/wp-content\/uploads\/2021\/02\/jass-website-logo-1.png","width":693,"height":132,"caption":"Jass Web"},"image":{"@id":"https:\/\/jassweb.com\/solved\/#\/schema\/logo\/image\/"}},{"@type":"Person","@id":"https:\/\/jassweb.com\/solved\/#\/schema\/person\/65c9c7b7958150c0dc8371fa35dd7c31","name":"Kirat","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/jassweb.com\/solved\/#\/schema\/person\/image\/","url":"https:\/\/jassweb.com\/solved\/wp-content\/litespeed\/avatar\/1261af3c9451399fa1336d28b98ea3bb.jpg?ver=1776403586","contentUrl":"https:\/\/jassweb.com\/solved\/wp-content\/litespeed\/avatar\/1261af3c9451399fa1336d28b98ea3bb.jpg?ver=1776403586","caption":"Kirat"},"sameAs":["http:\/\/jassweb.com"],"url":"https:\/\/jassweb.com\/solved\/author\/jaspritsinghghumangmail-com\/"}]}},"_links":{"self":[{"href":"https:\/\/jassweb.com\/solved\/wp-json\/wp\/v2\/posts\/32096","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jassweb.com\/solved\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jassweb.com\/solved\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jassweb.com\/solved\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jassweb.com\/solved\/wp-json\/wp\/v2\/comments?post=32096"}],"version-history":[{"count":0,"href":"https:\/\/jassweb.com\/solved\/wp-json\/wp\/v2\/posts\/32096\/revisions"}],"wp:attachment":[{"href":"https:\/\/jassweb.com\/solved\/wp-json\/wp\/v2\/media?parent=32096"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jassweb.com\/solved\/wp-json\/wp\/v2\/categories?post=32096"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jassweb.com\/solved\/wp-json\/wp\/v2\/tags?post=32096"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}