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Odd/Even Coding

Odd-Even Coding applies different transformation rules to letters based on their position in the word (1st, 2nd, 3rd, etc.). Letters at odd positions may be transformed one way (e.g., replaced by position numbers), while letters at even positions are transformed differently (e.g., shifted by +1). These problems test conditional rule application and positional awareness.

10Worksheets
200+Practice Questions
IntermediateDifficulty
2-3 hoursHours to Master

What You'll Learn

Introduction & Overview Why This Matters How to Solve Pro Tips & Tricks
Shortcut Methods Common Mistakes Practice Worksheets Exam Importance

Introduction to Odd/Even Coding

Odd-Even Coding applies different transformation rules to letters based on their position in the word (1st, 2nd, 3rd, etc.). Letters at odd positions may be transformed one way (e.g., replaced by position numbers), while letters at even positions are transformed differently (e.g., shifted by +1). These problems test conditional rule application and positional awareness.

Prerequisites

Understanding of odd and even positions (1-indexed) Alphabet position knowledge Basic transformation rules Conditional logic application
Why This Matters: Odd-Even Coding appears in 1-2 questions in SSC CGL and Banking PO exams. It tests conditional logic and positional reasoning.

How to Solve Odd/Even Coding Problems

1

Step 1: Identify the rule for odd positions and the rule for even positions

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Step 2: Determine the position number of each letter in the word (1st, 2nd, 3rd, ...)

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Step 3: Check if the position is odd or even

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Step 4: Apply the odd position rule to letters at odd positions

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Step 5: Apply the even position rule to letters at even positions

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Step 6: Combine the transformed letters in the same order

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Step 7: Present the coded word

Pro Strategy: First identify the word length and position numbers. Apply the appropriate rule based on whether the position is odd or even. Keep the order of letters the same.

Example Problem

Example: For a word, odd positions are coded as the position number of the letter, even positions are shifted by +1. Code 'CAB'. Solution: Step 1: Positions: 1st=C, 2nd=A, 3rd=B Step 2: Odd positions: 1st and 3rd → code as position numbers: C=3, B=2 Step 3: Even position: 2nd → shift +1: A+1=B Step 4: Coded word = 3 B 2 or '3B2' Answer: 3B2

Pro Tips & Tricks

  • Odd positions: 1st, 3rd, 5th, 7th, ...
  • Even positions: 2nd, 4th, 6th, 8th, ...
  • Common odd position rules: replace with position number, shift forward, capitalize
  • Common even position rules: shift backward, replace with opposite letter, leave unchanged
  • Write the word with position numbers (1,2,3...) above each letter for clarity
  • Mark odd and even positions before applying rules

Shortcut Methods to Solve Faster

Odd positions = positions where index % 2 == 1 (1-indexed)
Even positions = positions where index % 2 == 0
For a word of length n, there are ceil(n/2) odd positions and floor(n/2) even positions
The transformation for each position is independent of other positions

Common Mistakes to Avoid

Using 0-indexed positions instead of 1-indexed
Applying the odd rule to even positions or vice versa
Forgetting that position numbers start at 1, not 0
Not handling mixed output (numbers and letters) correctly

Ready to Master Odd/Even Coding?

Start with Worksheet 1 and work your way up to expert level! Each worksheet includes:

20 practice questions
Detailed solutions
Step-by-step explanations
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