Technical Consulting - Training and selecting candidates

Farmly is a coffee startup that connects producers to international buyers. They hired me in 2021 to provide technical consulting for their tech team.

We had weekly meetings with the team for training in technology applied to the company's scenario. We talked about:

• Scrum

• Discovery to Delivery process

• ReactJS

• Automated testing

• CI/CD

And in our last interaction I was asked to select and evaluate candidates for the fullstack developer position. I had already done this role in the companies I worked at as a leader, but as a service for a third party company it was my first opportunity.

• I asked the candidates to take some project from their portfolio to present its functioning and architecture, describing the technical choices. As the company focused on ReactJS, NodeJS and the use of GraphQL, we put these technologies as optional, making it clear that they would be important differentials.

• The candidates presented very interesting projects, in addition to talking about the technologies they have worked with.

• In the end to test development in practice I applied a code test:

Test

What does the code below do and is it correct?

function run(input: string) {
  let depth = 0;

  for (let c of input) {
    if (c === "(") {
      depth++;
    } else if (c === ")") {
      depth--;
    }
  }

  return depth === 0;
}

console.log(run("(()"))  
console.log(run("(())"))

Solution

• The code tests if the received string has the right number of parentheses and returns true or false

• However, it is wrong because it doesn't check the case of finding ")" without having opened the parenthesis;

function run(input: string) {
  let depth = 0;

  for (let c of input) {
    if (c === "(") {
      depth++;
    } else if (c === ")") {
      if (depth <= 0) {
        return false;
      }
      depth--;
    }
  }

  return depth === 0;
}

console.log(run(")(")) // false
console.log(run("(())")) // true  

Feedbacks

For all candidates I gave feedback on their resume, portfolio, LinkedIn, Github... Unfortunately this doesn't happen in all hiring processes which is a shame.