explanation.md

Fancy String Solution Guide

This README explains step-by-step how to solve the "Delete Characters to Make Fancy String" problem in various languages: C++, Java, JavaScript, Python, and Go. The goal is to ensure no three consecutive characters in the string are the same by deleting the minimum number of characters.

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Problem Understanding

We need to create a "fancy" string by removing characters so that no three consecutive characters are identical. To achieve this, we build a new result string by selectively adding characters from the input string while following the rule of avoiding three identical consecutive characters.

Solution Breakdown (All Languages)

Step 1: Initialize the Result Variable

• Purpose: Start with an empty container (string, list, or byte slice) to build the "fancy" string.
• Example: In Python, this would be an empty list; in JavaScript, an empty string; in Go, a byte slice.

Step 2: Loop Through Each Character in the String

• Purpose: Traverse the entire input string character by character.
• Implementation: Use a for loop to iterate through the characters in s.

Step 3: Check the Last Two Characters in the Result

• Purpose: Ensure that adding the current character will not result in three consecutive identical characters.
• Details:
  • If there are fewer than two characters in the result, add the current character without checks.
  • If there are already two characters in the result, check if both are the same as the current character:
    • If they are the same, skip adding the current character.
    • If they are different, add the current character to the result.

Step 4: Append Character to Result if Condition is Met

• Purpose: Conditionally add characters to avoid three consecutive identical characters.
• Details: This step is executed only if the condition in Step 3 allows it.

Step 5: Return the Final Result

• Purpose: Return the result in the desired format.
• Conversion:
  • In Python, use ''.join(result) to convert the list to a string.
  • In Go, convert the byte slice to a string before returning.
• Result: The final string is guaranteed to be a "fancy" string, with no three consecutive identical characters.

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Language-Specific Notes

C++ Code Explanation

1. Initialize an Empty String: string result;
2. Loop Through Each Character in s using a for loop.
3. Check the Last Two Characters in result before adding the current character.
4. Add or Skip the character based on whether it maintains the "fancy" requirement.
5. Return result after the loop completes.

Java Code Explanation

1. Initialize a StringBuilder: Use StringBuilder result = new StringBuilder();.
2. Loop Through Each Character in s by converting s to a character array.
3. Conditionally Add the character if it maintains the "fancy" condition.
4. Add Character to StringBuilder or skip as needed.
5. Return the Final Result: Convert StringBuilder to a string with result.toString().

JavaScript Code Explanation

1. Initialize an Empty String: let result = "";
2. Loop Through Each Character in s using a for loop.
3. Conditionally Add Characters to result by checking the last two characters.
4. Skip or Add the character based on the "fancy" condition.
5. Return the Result String after completing the loop.

Python Code Explanation

1. Initialize an Empty List: result = [] (lists allow easy appending).
2. Loop Through Each Character in s using a for loop.
3. Conditionally Append characters to result based on the last two items.
4. Add Character or Skip based on the "fancy" string condition.
5. Join List to String: Return ''.join(result) for the final fancy string.

Go Code Explanation

1. Initialize a Byte Slice: result := []byte{} for the final "fancy" string.
2. Loop Through Each Character in s with a for loop.
3. Conditionally Append Characters to result by checking the last two characters.
4. Add or Skip Characters to maintain the fancy requirement.
5. Convert Byte Slice to String: Return string(result) as the final result.