Integer listSize is read from input, then listSize strings are read from input and stored in ArrayList passengersToPick. listPassengers$()$ counts and outputs all possible orderings of names in remainPassengers. Complete the listPassengers$()$ base case to increment the value of optionsFound and output the following:

$"$#$"$

the value of optionsFound

$"$: $"$

each element of pickedPassengers followed by a space

End with a newline. Then, return the value of optionsFound for the base case. import java.util.Scanner;

import java.util.ArrayList;

public class Names $\{$

public static int listPassengers$($ArrayList remainPassengers, ArrayList pickedPassengers, int optionsFound$)\{$

int i;

String pick;

if $($remainPassengers$.$size$()==0)\{$

$/*$ Your code goes here $*/$

optionsFound$++$;

System.out.print$("$Number $"+$ optionsFound $+"$: $")$;

for $($i $=0$; i $<$ pickedTokens.size$()$; $++$i$)\{$

System.out.print$($pickedTokens$.$get$($i$)+"")$;

$\}$

System.out.println$()$;

return optionsFound;

$\}$

else $\{$

for $($i $=0$; i $<$ remainPassengers.size$()$; $++$i$)\{$

pick $=$ remainPassengers.get$($i$)$;

remainPassengers.remove$($i$)$;

pickedPassengers.add$($pick$)$;

optionsFound $=$ listPassengers$($remainPassengers$,$ pickedPassengers, optionsFound$)$;

remainPassengers.add$($i$,$ pick$)$;

pickedPassengers.remove$($pickedPassengers$.$size$()-1)$;

$\}$

return optionsFound;

$\}$

$\}$

public static void main$($String$[]$ args$)\{$

Scanner scnr $=$ new Scanner$($System$.$in$)$;

ArrayList passengersToPick $=$ new ArrayList$()$;

ArrayList picks $=$ new ArrayList$()$;

int listSize;

int i;

listSize $=$ scnr$.$nextInt$()$;

for $($i $=0$; i $<$ listSize; $++$i$)\{$

passengersToPick.add$($scnr$.$next$())$;

$\}$

System.out.println$("$All unique orderings:"$)$;

listPassengers$($passengersToPick$,$ picks, $0)$;

$\}$

$\}$

Explanation:

Increment optionsFound to count each unique sequence

Print "Number $"$ followed by the value of optionsFound

Print each picked token followed by a space

Print a newline

Return the updated value of optionsFound

Here is an explanation of the full makeSequence$()$ method:

Explanation:

Creating and printing every conceivable unique sequence $($ordering$)$ of the integers in the tokensToPick list is the aim.

It accomplishes this by building each sequence by recursively invoking itself.

The key parameters:

remainTokens $-$ the sublist of tokens that haven't been picked yet

pickedTokens $-$ the current sequence being built

optionsFound $-$ count of sequences generated so far$/////$

The base case is when remainTokens is empty. At that point:

Increment optionsFound to count this finished sequence

Publish the series together with its index number.

Return the updated count

For each recursive call:

Add one token from the remaining tokens to the end of the tokens that you have chosen.

Call makeSequence recursively to create sequences using the selected token

Reverse the decision by deleting the selected token and adding the original token to remainTokens.

This explores every possible ordering.

When we have completed selecting tokens to create a full sequence, the printing and counting take place in the base case.

So in summary, It builds up and prints every variant in a methodical manner using recursion.

This prints the selected tokens, separated by spaces on each line, for each distinct sequence along with an index number. To count every sequence, the updated optionsFound value is sent back.

Failed to compile

Names.java:$14$: error: cannot find symbol

for $($i $=0$; i $<$ pickedTokens.size$()$; $++$i$)\{$

$^$

symbol: variable pickedTokens

location: class Names

Names.java:$15$: error: cannot find symbol

System.out.print$($pickedTokens$.$get$($i$)+"")$;

$^$

symbol: variable pickedTokens

location: class Names

$2$ errors