🖥️ Input-Output (Machine Input-Output) - Complete Theory

Master machine logic - the pattern recognition reasoning topic!

🎯 What is Input-Output?

Input-Output (also called Machine Input-Output) tests your ability to:

• Identify sequential transformation patterns
• Track how words/numbers rearrange step-by-step
• Predict intermediate and final steps

Example:

Input:  cat 45 dog 12 bird 78
Step 1: 12 cat 45 dog bird 78
Step 2: 12 bird cat 45 dog 78
Step 3: 12 bird 45 cat dog 78
(Pattern: Numbers arranged ascending, words arranged alphabetically, alternating)

Key Concept: A “machine” rearranges input following a FIXED RULE. You find the rule and apply it!

📐 Types of Input-Output Patterns

1. Word Arrangement (Alphabetical)

2. Number Arrangement (Ascending/Descending)

3. Mixed Arrangement (Words + Numbers)

4. Mathematical Operations

5. Positional Shifting

6. Reversal Patterns

🔤 Common Patterns

Pattern 1: Alphabetical Arrangement

Rule: Words arranged in alphabetical order, one word per step

Example:

Input: dog cat bird elephant

Step 1: bird dog cat elephant (bird moved to start - alphabetically first)
Step 2: bird cat dog elephant (cat moved next)
Step 3: bird cat dog elephant (already sorted)

Final: bird cat dog elephant

Movement: One word moves to its correct position per step

Pattern 2: Number Arrangement (Ascending)

Rule: Numbers arranged in ascending order, one number per step

Example:

Input: 45 12 78 23

Step 1: 12 45 78 23 (smallest 12 moved to start)
Step 2: 12 23 45 78 (next smallest 23 moved)
Step 3: 12 23 45 78 (already sorted)

Final: 12 23 45 78

Pattern 3: Alternating Word-Number

Rule: Alternately arrange smallest number, then alphabetically first word

Example:

Input: cat 45 dog 12 bird 78

Step 1: 12 cat 45 dog bird 78 (smallest number first)
Step 2: 12 bird cat 45 dog 78 (alphabetically first remaining word)
Step 3: 12 bird 45 cat dog 78 (next smallest number)
Step 4: 12 bird 45 cat 78 dog (next alphabetical word)
Step 5: 12 bird 45 cat 78 dog (already done)

Final: 12 bird 45 cat 78 dog
Pattern: number, word, number, word, number, word

Pattern 4: Simultaneous Arrangement

Rule: In each step, smallest number to left, largest to right

Example:

Input: 45 12 78 23

Step 1: 12 45 23 78 (12 to left, 78 to right)
Step 2: 12 23 45 78 (23 to left of remaining, 45 stays)
Step 3: 12 23 45 78 (sorted)

Pattern 5: Word Length Based

Rule: Arrange by number of letters (ascending/descending)

Example:

Input: elephant cat bird dog

Step 1: cat elephant bird dog (3-letter word first)
Step 2: cat dog elephant bird (3, 3, then 4)
Step 3: cat dog bird elephant (3, 3, 4, then 8)

Pattern: Shortest word first

Pattern 6: Reverse Alphabetical

Rule: Arrange in reverse alphabetical order (Z to A)

Example:

Input: apple mango banana

Step 1: mango apple banana (M first in reverse)
Step 2: mango banana apple (B before A in reverse)

Final: mango banana apple

💡 Solved Examples

Example 1: Basic Alphabetical

Q:

Input: rose lily tulip daisy

What will be Step 2?

Solution:

Step 1: Identify pattern

Alphabetical order: daisy, lily, rose, tulip

Assume pattern: One word per step to correct position

Step 2: Apply pattern

Input: rose lily tulip daisy

Step 1: daisy rose lily tulip (daisy moved to first - alphabetically first)
Step 2: daisy lily rose tulip (lily moved to second position)

Answer: daisy lily rose tulip

Example 2: Number Arrangement

Q:

Input: 89 34 67 12 45

Step 1: 12 89 34 67 45
Step 2: 12 34 89 67 45
Step 3: ?

Solution:

Step 1: Identify pattern

Step 1: 12 moved to start (smallest)
Step 2: 34 moved to second (next smallest)

Pattern: Arranging in ascending order, one per step

Step 2: Find next

Remaining to arrange: 89, 67, 45
Next smallest = 45

Step 3: 12 34 45 89 67

Answer: 12 34 45 89 67

Example 3: Mixed Word-Number

Q:

Input: play 58 hand 32 over 91

Step 1: 32 play 58 hand over 91
Step 2: 32 hand play 58 over 91
Step 3: ?

Solution:

Step 1: Identify pattern

Input: play 58 hand 32 over 91

Step 1: 32 first (smallest number)
Step 2: hand next (alphabetically first word: hand < over < play)

Pattern: Alternating - number (ascending), word (alphabetical)

Step 2: Apply pattern

Step 3: Next is a number
Remaining numbers: 58, 91
Next smallest = 58

Step 3: 32 hand 58 play over 91

Answer: 32 hand 58 play over 91

Example 4: Simultaneous Movement

Q:

Input: 56 23 89 12 45

Step 1: 12 23 89 56 45
Step 2: ?

Solution:

Step 1: Analyze movement

Input:  56 23 89 12 45
Step 1: 12 23 89 56 45

What changed?
- 12 moved to position 1 (smallest)
- 23 stayed at position 2
- 89 stayed
- 56 and 45 shifted

Looks like: Smallest to left, keep moving

Step 2: Continue pattern

Step 1: 12 23 89 56 45
Now arrange remaining: 89, 56, 45

Next smallest from remaining = 45

Step 2: 12 23 45 89 56 OR 12 23 45 56 89?

Check if fully sorted or step-by-step:
If step-by-step: 12 23 45 89 56 (45 moved up)

Answer: 12 23 45 89 56 (if one element per step) OR 12 23 45 56 89 (if multiple movements allowed)

Example 5: Word Length Pattern

Q:

Input: train bus car bicycle

What is the final output if arranged by word length (shortest first)?

Solution:

Step 1: Count letters

train: 5 letters
bus: 3 letters
car: 3 letters
bicycle: 7 letters

Step 2: Arrange by length

Shortest first: 3, 3, 5, 7

bus (3)
car (3)
train (5)
bicycle (7)

Final: bus car train bicycle

Answer: bus car train bicycle

Example 6: Reverse Order

Q:

Input: 12 45 23 78 34

Step 1: 78 45 23 12 34
Step 2: 78 45 34 12 23
Step 3: ?

Solution:

Step 1: Identify pattern

Input:  12 45 23 78 34
Step 1: 78 ... (largest moved to first)
Step 2: 78 45 ... (next largest kept/moved)

Pattern: Descending order (largest to smallest)

Step 2: Continue

Sorted descending: 78, 45, 34, 23, 12

Step 1: 78 moved to first
Step 2: 45 at second, 34 moved up
Step 3: Continue arranging

Step 3: 78 45 34 23 12 (fully sorted descending)

Answer: 78 45 34 23 12

⚡ Quick Pattern Recognition Tips

Tip 1: Check First Step Carefully

First step reveals the core pattern:
- If smallest number moves → Ascending order
- If largest number moves → Descending order
- If alphabetically first word moves → Alphabetical order

Tip 2: Count Elements

If input has 5 elements and question asks for "Step 4":
Usually 4-5 steps needed for complete sorting

Tip 3: Alternating Pattern Recognition

If Step 1 moves a number, Step 2 moves a word:
Pattern is alternating word-number

Tip 4: Look for Unchanged Elements

Elements that don't move are already in correct position
Focus on elements that move!

⚠️ Common Mistakes

❌ Mistake 1: Assuming Complete Sort in One Step

Wrong: Input → Fully sorted in Step 1 ✗
Right: Usually one or two elements move per step ✓

❌ Mistake 2: Ignoring Intermediate Steps

Wrong: Jumping from Input directly to final ✗
Right: Track each step carefully ✓

❌ Mistake 3: Missing the Pattern Type

Wrong: Assuming always ascending order ✗
Right: Check if ascending, descending, alphabetical, or mixed ✓

❌ Mistake 4: Not Counting Steps

Wrong: "Step 3" means 3rd from final ✗
Right: "Step 3" means after 3 transformations from Input ✓

📊 Pattern Summary Table

📝 Practice Problems

Level 1: Basic

1.

Input: 45 12 78 23
Step 1: 12 45 78 23
Step 2: ?

2.

Input: dog cat bird elephant
What will be Step 1?

3.

Input: 67 23 89 12
If pattern is descending, what is final output?

Level 2: Medium

4.

Input: run 45 sit 12 walk 78

Step 1: 12 run 45 sit walk 78
Step 2: 12 run 45 sit 78 walk
Step 3: ?

5.

Input: tall boy runs fast here

Step 1: boy tall runs fast here
Step 2: boy fast tall runs here
Step 3: ?

Find the pattern.

Level 3: Hard

6.

Input: 15 pen 82 desk 43 book 67

Step 1: 15 book pen 82 desk 43 67
Step 2: 15 book 43 pen 82 desk 67
Step 3: ?

What is Step 5?

7.

Input: apple 23 mango 67 cherry 12 banana 45

Given that numbers are arranged ascending and words alphabetical alternately,
how many steps to reach final output?

🎯 Exam Strategy

Time Management:

• Per question (finding one step): 45-60 seconds
• For 5 input-output questions: 4-5 minutes

Quick Approach:

1. Identify pattern from Step 1 (15 sec)
2. Verify pattern with Step 2 (10 sec)
3. Apply to find required step (20 sec)
4. Verify answer (10 sec)

Priority:

• ✅ Simple number/word sorting - 40 sec
• ✅ Alternating patterns - 50 sec
• ⏭️ Complex multi-rule patterns - 75+ sec

🔗 Related Topics

Uses Concepts From:

• Number Series - Pattern recognition
• Coding-Decoding - Rule identification
• Alphabetical ordering

Related Reasoning Topics:

• Alphanumeric Series - Mixed sequences
• Logical sequencing

Practice:

• Input-Output Questions

Master Input-Output - Find the pattern, track each step! 🖥️