洞穴,惠勒和背部
背景 在Burrows-Wheeler变换(BWT)是一个字符串的字符的可逆置换的结果在对某些类型的字符串如纯文本相似字符大运行。例如,它在bzip2压缩算法中使用。 BWT定义如下: 给定一个输入字符串,例如codegolf,计算它的所有可能的旋转并将它们按字典顺序排序: codegolf degolfco egolfcod fcodegol golfcode lfcodego odegolfc olfcodeg 字符串的BWT codegolf是由该字符串的每个字符的最后一个字符组成的字符串,即该块的最后一列。因为codegolf,这产生了fodleocg。 就其本身而言,这种转换是不可逆的,因为字符串codegolf和golfcode导致相同的字符串。但是,如果我们知道字符串以结束f,则只有一个可能的原像。 任务 实现一个渐进式程序或函数,该程序或函数从STDIN读取单个字符串,或者作为命令行或函数参数读取并打印或返回BWT或它的输入字符串的倒数。 如果输入字符串不包含空格,则您的提交应在输入后附加一个空格并计算BWT。 如果输入字符串已经包含一个空格,则它应该计算具有尾随空格的BWT的原像,并去除该空格。 例子 INPUT: ProgrammingPuzzles&CodeGolf OUTPUT: fs&e grodllnomzomaiCrGgPePzu INPUT: fs&e grodllnomzomaiCrGgPePzu OUTPUT: ProgrammingPuzzles&CodeGolf INPUT: bt4{2UK<({ZyJ>LqQQDL6!d,@:~L"#Da\6%EYp%y_{ed2GNmF"1<PkB3tFbyk@u0#^UZ<52-@bw@n%m5xge2w0HeoM#4zaT:OrI1I<|f#jy`V9tGZA5su*b7X:Xn%L|9MX@\2W_NwQ^)2Yc*1b7W<^iY2i2Kr[mB;,c>^}Z]>kT6_c(4}hIJAR~x^HW?l1+^5\VW'\)`h{6:TZ)^#lJyH|J2Jzn=V6cyp&eXo4]el1W`AQpHCCYpc;5Tu@$[P?)_a?-RV82[):[@94{*#!;m8k"LXT~5EYyD<z=n`Gfn/;%}did\fw+/AzVuz]7^N%vm1lJ)PK*-]H~I5ixZ1*Cn]k%dxiQ!UR48<U/fbT\P(!z5l<AefL=q"mx_%C:2=w3rrIL|nghm1i\;Ho7q+44D<74y/l/A)-R5zJx@(h8~KK1H6v/{N8nB)vPgI$\WI;%,DY<#fz>is"eB(/gvvP{7q*$M4@U,AhX=JmZ}L^%*uv=#L#S|4D#< OUTPUT: <#Q6(LFksq*MD"=L0<f^*@I^;_6nknNp;pWPBc@<A^[JZ?\B{qKc1u%wq1dU%;2)?*nl+U(yvuwZl"KIl*mm5:dJi{\)8YewB+RM|4o7#9t(<~;^IzAmRL\{TVH<bb]{oV4mNh@|VCT6X)@I/Bc\!#YKZDl18WDIvXnzL2Jcz]PaWux[,4X-wk/Z`J<,/enkm%HC*44yQ,#%5mt2t`1p^0;y]gr~W1hrl|yI=zl2PKU~2~#Df"}>%Io$9^{G_:\[)v<viQqwAU--A#ka:b5X@<2!^=R`\zV7H\217hML:eiD2ECETxUG}{m2:$r'@aiT5$dzZ-4n)LQ+x7#<>xW)6yWny)_zD1*f @F_Yp,6!ei}%g"&{A]H|e/G\#Pxn/(}Ag`2x^1d>5#8]yP>/?e51#hv%;[NJ"X@fz8C=|XHeYyQY=77LOrK3i5b39s@T*V6u)v%gf2=bNJi~m5d4YJZ%jbc!<f5Au4J44hP/(_SLH<LZ^%4TH8:R INPUT: <#Q6(LFksq*MD"=L0<f^*@I^;_6nknNp;pWPBc@<A^[JZ?\B{qKc1u%wq1dU%;2)?*nl+U(yvuwZl"KIl*mm5:dJi{\)8YewB+RM|4o7#9t(<~;^IzAmRL\{TVH<bb]{oV4mNh@|VCT6X)@I/Bc\!#YKZDl18WDIvXnzL2Jcz]PaWux[,4X-wk/Z`J<,/enkm%HC*44yQ,#%5mt2t`1p^0;y]gr~W1hrl|yI=zl2PKU~2~#Df"}>%Io$9^{G_:\[)v<viQqwAU--A#ka:b5X@<2!^=R`\zV7H\217hML:eiD2ECETxUG}{m2:$r'@aiT5$dzZ-4n)LQ+x7#<>xW)6yWny)_zD1*f @F_Yp,6!ei}%g"&{A]H|e/G\#Pxn/(}Ag`2x^1d>5#8]yP>/?e51#hv%;[NJ"X@fz8C=|XHeYyQY=77LOrK3i5b39s@T*V6u)v%gf2=bNJi~m5d4YJZ%jbc!<f5Au4J44hP/(_SLH<LZ^%4TH8:R OUTPUT: bt4{2UK<({ZyJ>LqQQDL6!d,@:~L"#Da\6%EYp%y_{ed2GNmF"1<PkB3tFbyk@u0#^UZ<52-@bw@n%m5xge2w0HeoM#4zaT:OrI1I<|f#jy`V9tGZA5su*b7X:Xn%L|9MX@\2W_NwQ^)2Yc*1b7W<^iY2i2Kr[mB;,c>^}Z]>kT6_c(4}hIJAR~x^HW?l1+^5\VW'\)`h{6:TZ)^#lJyH|J2Jzn=V6cyp&eXo4]el1W`AQpHCCYpc;5Tu@$[P?)_a?-RV82[):[@94{*#!;m8k"LXT~5EYyD<z=n`Gfn/;%}did\fw+/AzVuz]7^N%vm1lJ)PK*-]H~I5ixZ1*Cn]k%dxiQ!UR48<U/fbT\P(!z5l<AefL=q"mx_%C:2=w3rrIL|nghm1i\;Ho7q+44D<74y/l/A)-R5zJx@(h8~KK1H6v/{N8nB)vPgI$\WI;%,DY<#fz>is"eB(/gvvP{7q*$M4@U,AhX=JmZ}L^%*uv=#L#S|4D#< INPUT: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa OUTPUT: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaab aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa INPUT: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaab aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa OUTPUT: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa …