1. Password Reset

function solve(params) {
  let str = params.shift();
  let password = "";
  let result = "";

  for (let param of params) {
    let tokens = param.split(" ");
    let command = tokens[0];

    if (command === "TakeOdd") {
      if (str.length > 0) {
        for (let i = 0; i < str.length; i++) {
          if (i % 2 === 1) {
            password += str[i];
          }
        }
      }

      result += `${password}\n`;
    } else if (command === "Cut") {
      let index = Number(tokens[1]);
      let length = Number(tokens[2]);

      let cutted = password.substr(index, length);

      password = password.replace(cutted, "");

      result += `${password}\n`;
    } else if (command === "Substitute") {
      let substring = tokens[1];
      let substitute = tokens[2];

      if (password.includes(substring)) {
        while (password.includes(substring)) {
          password = password.replace(substring, substitute);
        }
        result += `${password}\n`;
      } else {
        result += "Nothing to replace!\n";
      }
    } else if (command === "Done") {
      result += `Your password is: ${password}`;
    }
  }

  return result;
}