Coding and Decoding || Reasoning

 

Understanding Coding and Decoding

Coding and decoding involve transforming information or messages from one form to another based on specific rules or algorithms. These concepts are widely used in computer programming, cryptography, and data transmission.

Below are the key types of coding and decoding:

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1. Letter Coding

In letter coding, letters in a word are replaced by other letters following a specific pattern to generate a coded word. The pattern can involve shifting letters by a fixed number of positions, applying arithmetic operations, or following a sequence-based transformation.

Example:

If the word "FAUCET" is coded as "GBWEHW", we can observe the pattern:

• F → G (+1)
• A → B (+1)
• U → W (+2)
• C → E (+2)
• E → H (+3)
• T → W (+3)

Applying the same pattern to the word "CODING":

• C → D (+1)
• O → P (+1)
• D → F (+2)
• I → K (+2)
• N → Q (+3)
• G → J (+3)

Thus, "CODING" is coded as "DPFKQJ".

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2. Number or Symbol Coding

In this type of coding, each letter in a word is assigned a specific number or symbol. The coded word is then derived by replacing its letters accordingly.

Example:

If:

• "WORDS" → "3#51@"
• "SEAR" → "@9!5"

By analyzing the letter-to-symbol mapping:

• W = 3
• O = #
• R = 5
• D = 1
• S = @
• E = 9
• A = !

Now, applying the same pattern to the word "DARE":

• D = 1
• A = !
• R = 5
• E = 9

Thus, "DARE" is coded as "1!59".

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3. Substitution-Based Coding

In this method, words in a sentence are replaced by other words, letters, numbers, or symbols based on a specific pattern. Identifying the pattern allows us to decode or encode words.

Example:

Given the coded sentences:

• "an endemic is disease" → "pu bt ys ej"
• "any disease is curable" → "ar bt xw ej"
• "any endemic is not epidemic" → "ys ar mo bt hz"

By comparing sentences, we can deduce the word-to-code mapping:

• "is" appears in all three sentences → bt
• "disease" appears in the first and second sentences → ej
• "endemic" appears in the first and third sentences → ys
• "any" appears in the second and third sentences → ar

Using this pattern, we can decode:

• "curable" appears only in the second sentence → xw
• "epidemic" appears only in the third sentence → mo

Final Answers:

• The word "curable" is coded as "xw".
• The word coded as "mo" is "epidemic".