-- The Computer Language Benchmarks Game -- http://benchmarksgame.alioth.debian.org/ -- contributed by Jim Roseborough -- modified by Victor Tang -- optimized & replaced inefficient use of gsub with gmatch -- partitioned sequence to prevent extraneous redundant string copy seq = io.read("*a") ilen, seq = #seq, seq:gsub('>[^%c]*%c*', ''):gsub('%c+', '') clen = #seq local variants = { 'agggtaaa|tttaccct', '[cgt]gggtaaa|tttaccc[acg]', 'a[act]ggtaaa|tttacc[agt]t', 'ag[act]gtaaa|tttac[agt]ct', 'agg[act]taaa|ttta[agt]cct', 'aggg[acg]aaa|ttt[cgt]ccct', 'agggt[cgt]aa|tt[acg]accct', 'agggta[cgt]a|t[acg]taccct', 'agggtaa[cgt]|[acg]ttaccct', } local subst = { B='(c|g|t)', D='(a|g|t)', H='(a|c|t)', K='(g|t)', M='(a|c)', N='(a|c|g|t)', R='(a|g)', S='(c|g)', V='(a|c|g)', W='(a|t)', Y='(c|t)' } function countmatches(variant) local n = 0 variant:gsub('([^|]+)|?', function(pattern) for _ in seq:gmatch(pattern) do n = n + 1 end end) return n end for _, p in ipairs(variants) do io.write( string.format('%s %d\n', p, countmatches(p)) ) end function partitionstring(seq) local seg = math.floor( math.sqrt(#seq) ) local seqtable = {} for nextstart = 1, #seq, seg do table.insert(seqtable, seq:sub(nextstart, nextstart + seg - 1)) end return seqtable end function chunk_gsub(t, k, v) for i, p in ipairs(t) do t[i] = p:find(k) and p:gsub(k, v) or t[i] end return t end seq = partitionstring(seq) for k, v in pairs(subst) do chunk_gsub(seq, k, v) end seq = table.concat(seq) io.write(string.format('\n%d\n%d\n%d\n', ilen, clen, #seq))