F$1$Omal MaSource Codeesc$066$ EightQueens.cThere are n arrays A permutation is oenerted we let is t bonHow do you generate all permutations of n arays?Question $67$For example, permutations for the $3$ arrays $(1,2),(3,4),(5,6)$ are $(1,3,5$L$(0\mathrm{.}3\mathrm{.}6$L$(1,4590\mathrm{.}4623(2,3,6),(2,4,5),$ and $(2,4,6)$F$2$Similar to finding permutations ofa string, t divides the ninput arrays into two parts the frt ary andthe remaining n$-$l arays. After an element is selected from the first array, it contines to flndidentical to the nrocess to findnttiListing $6-24.$Listing $6-24.$ Java Code to Permute Arraysvold permute$($Array se tackeIntegep$)$:permuteCore$($arrays$,$ permutation$)$:vold permuteCore $($Arraylisteint$[]>$ arrays, StackeIntege permutation$)$P ot nrintin$($pernutation$)$ ;return;g Interviews: Questions, Analysis & Solutions$5.$get $($pernutation$.$size$())$;$1$ntl y ArTaVlength; $++1)$permutation $.$ push$($ateyon$)$ :F$3$Question $68$ Please generate all combi'abe are at$"$eab$.$act."he$.$ andF$1$Based on Divide and ConquerSuppose the length of a given string is nand we are going to find one of its combinatns withThere are two choices for the firsche r eharacier and the oe nidetscombination, and it continues to select m$-1$ characters from the remaining eldharen ndeTherefore combinatinns of a un trinn bndListing $6-25.$ Java Code for String Combinations $($Version $1)$F$2$void combination$(5$tring susackeCharacten$()$;torlint :i$($e str$.$length$()$; $++$ i$)(\}$ofllvoid conbination $($String str$,$ int index, int nunber, StackeCharacter result$)($sf$($nunberCeding lntervies Oustions, Anayis & Sotns$0).$out.println$($result$)$;$1$f$($index str$.$length$())$return;pre perfeetnUndingFAQuestion $69$F$2$Median in a Streamofa gven string For eangle, nt gyly$,$ deyvalue of the two numbers in the middecontainrleut utes dyamiewhen they are deserialized. Let's find an appeogrlate dta sntue hd$80$order te ct of s eWe can also keep the array sorted while addingew umbeF$3$bumbers will he moed fene ate numbers into get the median since it only takenumber, Additionally, the time to get the median can be opeimind Cpoint o e isa binary search tree because it only costs Og nHowever, the time complexity is O$($n$)$ for the wont caenta to recond the number of nodes in subrees are secevaryo$($logn$)$ time to get the meu i errh tree AVL, to avoid the wost calw the balance factor of a node in AvLteand left subtree. Wemayeriht suhtree and eft subtree lt cots gnde into an AVL and O$)$ time to get the median for acaeh$be baBpernutetorecombination $($str$,0,$ i$,$ result$)$;partition method, which ls discused in the ectin Seurh nt Srt fr edd a