What is Input Output
Machine input or Input Output is a question type, where the candidate is given some kind of word and number arrangement. With each subsequent operation, the arrangement of the words and numbers changes. These operations are performed until a final arrangement is reached or is performed in loop. The student is required to identify the hidden pattern in the rearrang0ement and apply it to the questions.
A word arrangement machine when given an input of words, rearranges them following a particular rule in each step. The following is an illustration of input and steps rearrangement.
Input : Camp Rule Show Mouth Fast
Step I : Show Camp Rule Mouth Fast
Step II : Show Rule Camp Mouth Fast
Step III: Show Rule Mouth Camp Fast
Step IV: Show Rule Mouth Fast Camp This is the final arrangement and STEP IV is the last step for this input.
What should be the last step of the following input?
INPUT: Coal Steer Brief Nap Blast Cry
The given rearrangement has a pattern that can be followed from the input step to the final step, which is Step IV. Observe carefully. The rearrangement follows the following patterns:
1. The rearrangement is taking place from left to right.
2. The rearrangement is taking place one word at a time.
3. The rearrangement is done on the basis of decreasing alphabetic order.
NOTE: To understand the pattern, often it is sufficient to look at the input, 1st, 2nd and final steps of the arrangement.
Now if we apply the same pattern rules to the second input given, we can immediately tell what the output (final step after rearrangement) would be:
INPUT: Coal Steer Brief Nap Blast Cry
OUTPUT: Steer Nap Cry Coal Brief Blast
TYPES OF QUESTIONS
Based on the logic used behind the rearrangement, we can classify these types of questions as:
A. Rearrangements based on Ordering:
Words are arranged alphabetically (forward or reversed) as per their positions in the dictionary while numbers are arranged in ascending/descending order.
Both words and numbers could be arranged individually or simultaneously in each step. The rearrangement can start from the leftmost side or the rightmost side of the sentence and sometimes even simultaneously from both the ends. The rearrangement could either start with a word or a number. Whatever the finer details may be, in these kinds of rearrangements, one or two words/numbers are shifted at a time, without changing the order of the remaining words/numbers.
Input : 71 cowboy dye zirconium 92 45 66 bandit
Step I : 45 71 cowboy dye 92 66 bandit zirconium
Step II : 45 66 71 cowboy 92 bandit dye zirconium
Step III: 45 66 71 92 bandi t cowboy dye zirconium
Here, Step III is the final step and the rearrangement is done simultaneously from both front and back ends. The rearrangements are done this way : the numbers are arranged in ascending order one by one from the left end, with the next biggest number being added to the right of the previous number. The words are arranged in descending order one by one from the right end, with the last word in the dictionary going to the rightmost end, and earlier entries in the dictionary getting added in subsequent steps to the left of that word.
B. Rearrangements based on Interchanging the Positions of Words and Numbers:
Specific positions are selected and the positions of only those words/numbers are exchanged. The positions of all others remain unchanged.
Input : 102 bobby indica 49 diamond 22 gas figure 75 20
Step I : 20 bobby indica 49 diamond 22 gas figure 75 102
'bobby' is already arranged, so we will move on to the next element.
Step II : 20 bobby 22 49 diamond indica gas figure 75 102
Step III: 20 bobby 22 diamond 49 indica gas figure 75 102
Step IV : 20 bobby 22 diamond 49 figure gas indica 75 102
Step V : 20 bobby 22 diamond 49 figure 75 indica gas 102
Step VI : 20 bobby 22 diamond 49 figure 75 gas indica 102
Step VII : 20 bobby 22 diamond 49 figure 75 gas 102 indica
Step VII is the final step of the input. The underlined words are used to indicate the words that will be interchanged in the each subsequent step.
C. Rearrangements based on Mathematical operations:
Some mathematical operation (like squaring the number, adding the digits within the number, some common number added/subtracted/multiplied/divided to each number etc.) is applied on the numbers in each step.
Input : 17 25 92 88 19 52
Step I : 10 25 92 88 19 50
Step II : 10 20 92 88 10 50
Step III: 10 20 90 80 10 50
Step III is the final step. Clearly in this example, the unit’s digits of the left most and right most number are simultaneously being subtracted from the numbers themselves. This is followed by the number to the right of the left most one, and to the left of the right most one.
TIPS ABOUT NUMBER OF STEPS
1. If there are ‘n’ words/digits in the input then at most ‘n-1’ steps are required to rearrange it completely.
2. Number of words/digits arranged until the present step is greater than or equal to the present step number.
3. If input is not given we cannot determine the previous step from given step number or we cannot determine input from given step number.
Race Institute, Hyderabad