Input Output Questions and Answers

Answer: D

Correct answer: Cannot be determined

The same irreversibility applies whether you are asked for the input or for an earlier step. Each move destroys the record of where the moved element used to sit, so working backwards from step III to step I is no more possible than working back to the input - several different step I lines lead to the same step III.

Answer: B

Input : w y 22 s 31 16 47 t 
Step 1 : 47 w y 22 s 31 16 t 
Step 2 : 47 s w y 22 31 16 t 
Step 3 : 47 s 31 w y 22 16 t 
Step 4 : 47 s 31 t w y 22 16 
Step 5 : 47 s 31 t 22 w y 16 
Step 6 : 47 s 31 t 22 w 16 y 

Answer: C

Input : c w 21 42 58 H B 78
Step I : 78 c w 21 42 58 H B
Step II : 78 B c 58 w 21 42 H 
Step III : 78 B 58 c w 21 42 H 
Step IV : 78 B 58 c 42 w 21 H 
Step V : 78 B 58 c 42 H w 21 
Step VI : 78 B 58 c 42 H 21 w

Answer: D

Correct answer: Cannot be determined

Every step of these machines moves one element to a fixed position and lets the rest close up behind it, so the original positions of the elements still waiting are lost as soon as the first move is made. The process runs one way only: from a later line you can say what will follow but never what came before, because many different inputs produce the same intermediate line. That is why the answer to any “what was the input” question of this kind is that it cannot be determined.

Answer: C

Step III : 88 butylene 77 superpose Hizballah Lapplander 37 55
Step IV : 88 butylene 77 Hizballah superpose Lapplander 37 55
Step V : 88 butylene 77 Hizballah 55 superpose Lapplander 37 
Step VI : 88 butylene 77 Hizballah 55 Lapplander superpose 37 
Step VII : 88 butylene 77 Hizballah 55 Lapplander 37 superpose

Answer: B

Input : goad teal Asio 11 91 88 43 soul 
Step I : 91 goad teal Asio 11 88 43 soul 
Step II : 91 Asio goad teal 11 88 43 soul 
Step III : 91 Asio 88 goad teal 11 43 soul 
Step IV : 91 Asio 88 goad 43 teal 11 soul 
Step V : 91 Asio 88 goad 43 soul teal 11 
Step VI : 91 Asio 88 goad 43 soul 11 teal

Answer: C

Input : star 24 anabas 83 53 trace 67 hint
Step I   : anabas star 24 83 53 trace 67 hint
Step II  : anabas 24 star 83 53 trace 67 hint
Step III : anabas 24 hint star 83 53 trace 67
Step IV  : anabas 24 hint 53 star 83 trace 67
Step  V  : anabas 24 hint 53 star 67 83 trace
Step VI  : anabas 24 hint 53 star 67 trace 83

Answer: A

Input :  stabber house 38 65 all mead 85 58
Step I   : 38 stabber house 65 all mead 85 58
Step II  : 38 stabber 58 house 65 all mead 85 
Step III : 38 stabber 58 mead house 65 all 85 
Step IV  : 38 stabber 58 mead house 65 85 all 

Answer: D

Correct answer: Cannot be determined

Every step of these machines moves one element to a fixed position and lets the rest close up behind it, so the original positions of the elements still waiting are lost as soon as the first move is made. The process runs one way only: from a later line you can say what will follow but never what came before, because many different inputs produce the same intermediate line. That is why the answer to any “what was the input” question of this kind is that it cannot be determined.

Answer: B

Input :  sexual 87 distinctions 92 cheapest bat 86 ant 48
Step I   : 48 sexual 87 distinctions 92 cheapest bat 86 ant
Step II  : 48 sexual 86 87 distinctions 92 cheapest bat ant
Step III : 48 sexual 86 distinctions 87 92 cheapest bat ant