Leetcode Blind 75 C++: Encode and Decode Strings

Hey Everyone, Im going over the Blind 75, so decided to make a series on them to help solidify concepts prior to interviews. Below I have attached my notes from doing questions and if have any other questions feel free to let me know!

Thank you

[GChief]

//Input
/*
We are given a list of strings
*/

//What DS/Algo/Technique
/*
Delimiter-based encoding approach.
*/

//What to do with the data
/*
Encoding
we have a list of strings
make them into a single string
Steps:
1. Initialize an empty string 'encoded'
2. Iterate over each string 's' in our list of strings 'strs'
2.1 We will append the length of string to encoded followed bya. delimiter
2.2 Append our string (s) to encoded
3. Return encoded

Decoding
take the single string
make the single string into a list of strings

Steps:
1. Initialize an empty vector of strings 'decoded'
2. Initialize an index 'i' to 0
3. While i is less than the length of the encoded string
3.1 Find the position of the delimiter in the encoded string starting from index 'i'
3.2 Extract the length of the string from the encoded string based on the delimiter position
3.3 Move the index i to the position after the delimiter
3.4 Extract the actual string form the encoded string based on the length
3.5 Append the extracted string to decoded
3.6 Update the index i to the position after the extracted string
4. Return the decoded


Creating our delimiter
It will be a private character indicaded as '/'
*/

//Output
/*
We need to fill in the functions for encoding and decoding.
For encoding we need to return the encoded string.
For decoding we need to return the lof decoded strings.
*/

class Codec {
public:
// Encodes a list of strings to a single string.
string encode(vector<string>& strs) {
//Step 1
string encoded;
//Step 2
for(const string& s: strs){
//2.1
encoded += to_string(s.length()) + delimiter;
//2.2
encoded += s;
}

//Step 3
return encoded;
}

// Decodes a single string to a list of strings.
vector<string> decode(string s) {
//Step 1
vector<string> decoded;
//Step 2
int i = 0;

//Step 3
while(i < s.length()){
//3.1
size_t delimiterPos = s.find(delimiter, i);
//3.2
int length = stoi(s.substr(i, delimiterPos - i));
//3.3
i = delimiterPos + 1;
//3.4
string str = s.substr(i, length);
//3.5
decoded.push_back(str);
//3.6
i += length;
}
//Step 4
return decoded;
}
//Delimiter
private:
const char delimiter = '/';
};

// Your Codec object will be instantiated and called as such:
// Codec codec;
//