encodeDecode.js

// String Encode and Decode
// Design an algorithm to encode a list of strings to a single string. The encoded string is then decoded back to the original list of strings.

// Please implement encode and decode

// Example 1:

// Input: ["neet","code","love","you"]

// Output:["neet","code","love","you"]
// Example 2:

// Input: ["we","say",":","yes"]

// Output: ["we","say",":","yes"]
// Constraints:

// 0 <= strs.length < 100
// 0 <= strs[i].length < 200
// strs[i] contains only UTF-8 characters.
class Solution {
    /**
     * @param {string[]} strs
     * @returns {string}
     */
    encode(strs) {
        let result = '';
        for (let s of strs) {
            result += `${s.length}#${s}`;
        }

        return result;
    }

    /**
     * @param {string} str
     * @returns {string[]}
     */
    decode(str) {
        let result = [];
        let i = 0;

        while (i < str.length) {
            let j = i;
            while (str[j] !== '#' && j < str.length) {
                j++;
            }

            let length = parseInt(str.substring(i, j), 10);
            i = j + 1;
            j = i + length;
            result.push(str.substring(i,j));
            i = j;
        }
        return result;
    }
}
const solution = new Solution();

// Example 1
let input1 = ["neet","code","love","you"];
console.log(solution.encode(input1));
console.log(solution.decode(input1));