encodeDecodeStrings.md

Description:

Write an algorithm to encode a list of strings to a single string, and then decode it back to the original list. Implement both encode and decode functions.

Examples

Example 1:
Input: ["learn", "datastructure", "algorithms", "easily"]
Output: ["learn", "datastructure", "algorithms", "easily"]

Example 2:
Input: ["one", "two", "three"]
Output: ["one", "two", "three"]

Example 3:
Input: ["#", "##", "abc#def"]
Output: ["#", "##", "abc#def"]

Algorithm

Encode

1. Initialize an empty string encodedStr.
2. For each string in the input array, append its length, a delimiter (e.g., #), and the string itself to encodedStr.
3. Return the concatenated string.

Decode

1. Initialize an empty array decodedStrArr and an index variable i = 0.
2. While i is less than the length of the encoded string:
   • Find the next delimiter (#) to determine the length prefix.
   • Parse the length, extract the substring of that length, and add it to the result array.
   • Move the index past the extracted substring and repeat.
3. Return the array of decoded strings.

Complexity

• Time Complexity: O(n) for both encoding and decoding, where n is the total number of characters in all strings.
• Space Complexity: O(n), for the encoded string and the decoded array.