Python: Restore the original string by entering the compressed string with specified rule

Last update on April 17 2025 13:05:41 (UTC/GMT +8 hours)

Restore Compressed String

When character are consecutive in a string , it is possible to shorten the character string by replacing the character with a certain rule. For example, in the case of the character string YYYYY, if it is expressed as # 5 Y, it is compressed by one character.

Write a Python program to restore the original string by entering the compressed string with this rule. However, the # character does not appear in the restored character string.

Note: The original sentences are uppercase letters, lowercase letters, numbers, symbols, less than 100 letters, and consecutive letters are not more than 9 letters.

Input:
The restored character string for each character on one line.
Original text: XY#6Z1#4023
XYZZZZZZ1000023
Original text: #39+1=1#30
999+1=1000

Sample Solution:

Python Code:

# Define a function 'restore_original_str' with parameter 'a1'
def restore_original_str(a1):
    # Initialize an empty string 'result' to store the restored original text
    result = ""
    # Initialize index 'ind' to 0
    ind = 0
    # Set 'end' to the length of the input string 'a1'
    end = len(a1)
    
    # Start a while loop until 'ind' reaches the end of the input string
    while ind < end:
        # Check if the current character is '#' (indicating a pattern)
        if a1[ind] == "#":
            # Append the character at the next position repeated by the integer at the position after that
            result += a1[ind + 2] * int(a1[ind + 1])
            # Move the index 'ind' to the position after the pattern
            ind += 3
        else:
            # If not a pattern, append the current character
            result += a1[ind]
            # Move the index 'ind' to the next position
            ind += 1
    
    # Return the restored original text
    return result

# Print a statement indicating the original text and the input string
print("Original text:", "XY#6Z1#4023")
# Call the 'restore_original_str' function with the input string and print the result
print(restore_original_str("XY#6Z1#4023"))

# Print another statement with a different input string
print("Original text:", "#39+1=1#30")
# Call the 'restore_original_str' function with the second input string and print the result
print(restore_original_str("#39+1=1#30"))

Sample Output:

Original text: XY#6Z1#4023
XYZZZZZZ1000023
Original text: #39+1=1#30
999+1=1000

Explanation:

Here is a breakdown of the above Python code:

• Define a function "restore_original_str()" to restore the original text from a given pattern.
• Initialize an empty string 'result' to store the restored original text.
• Initialize index 'ind' to 0 and set 'end' to the length of the input string 'a1'.
• Use a while loop to iterate through the characters in the input string.
• Check if the current character is '#' indicating a pattern.
• If it's a pattern, append the character at the next position repeated by the integer at the position after that.
• Move the index 'ind' to the position after the pattern.
• If it's not a pattern, append the current character and move the index 'ind' to the next position.
• Continue the loop until 'ind' reaches the end of the input string.
• Return the restored original text.

Visual Presentation:

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to decompress a string that uses a marker format like "#" for repeated characters.
• Write a Python program to convert a compressed string with multiple markers into its original uncompressed form.
• Write a Python program to restore an original string from a compressed format where sequences of characters are represented by a symbol and count.
• Write a Python program to parse a compressed string containing embedded count markers and rebuild the full text.

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Python Code Editor:

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