Technical interview test

In this test we want to have a conversation with the potential hire around code. This is a live coding test. We have 60 minutes scheduled, 30-45 minutes should be coding and the rest will be general conversation about the test or anything else that might arise.

    struct Person {
        let name: String
        var children: [Person] = []
    }
    
    let peoples = [
        Person(name: "Mary",
               children: [Person(name: "Roi",
                                 children: [
                                   Person(name: "Ali", children: [Person(name: "Chip")]),
                                   Person(name: "Rudolf", children: [Person(name: "Judith"), Person(name: "Christine")])
                                   ]
                                ),
                          Person(name: "Aaron", children: [Person(name: "Mohamed")])
                         ]),
        Person(name: "Eve", children: [Person(name: "Ryan")])
        ]
    
    
    let expectedString =
    """
    |--Mary
    |  |--Roi
    |  |  |--Ali
    |  |  |  |--Chip
    |  |  |--Rudolf
    |  |  |  |--Judith
    |  |  |  |--Christine
    |  |--Aaron
    |  |  |--Mohamed
    |--Eve
    |  |--Ryan
    """
    
    if result == expectedString {
        print("Perfect")
    } else {
        print(result)
    }

What to look for in the interview process in general:

The planning phase before writing code
Does the candidate verbalize the thinking process
The time is takes to complete. It needs to be under 30 minutes.
The code quality
If the thinking process clear?
Does the candidate ask questions?
Does the candidate have a good understanding of the problem?
Does the candidate get stuck? This is not a good sign.

We should not influence the candidate in any way, we want to leave him/her to think and code on their own. We should not give hints or help. If we need to help it’s a weakness sign

This is the Kotlin equivalent:

fun main(args: Array<String>) {

    val persons = listOf(
        Person("Mary", children = listOf(
            Person("Roi", children = listOf(
                Person("Ali", children = listOf(Person("Chip"))),
                Person("Rudolf", children = listOf(Person("Judith"), Person("Christine")))
            )),
            Person("Aaron", children = listOf(Person("Mohammed")))
        )),
        Person("Eve", children = listOf(Person("Michael")))
    )

    val expectedString = """|--Mary
|  |--Roi
|  |  |--Ali
|  |  |  |--Chip
|  |  |--Rudolf
|  |  |  |--Judith
|  |  |  |--Christine
|  |--Aaron
|  |  |--Mohammed
|--Eve
|  |--Michael"""

    val result = printPersonTree(persons)

    if (result == expectedString) {
        println("Perfect")
    } else {
        println(result)
    }
}

data class Person(val name: String, val children: List<Person> = emptyList())


fun printPersonTree(persons: List<Person>, level: Int = 0, first: Boolean = true) : String {
    val sb = StringBuilder()
    for ((index, person) in persons.withIndex()) {
        if(!first || index > 0){
            sb.append("\n")
        }
        sb.append("|  ".repeat(level))
            .append("|--")
            .append(person.name)
        sb.append(printPersonTree(person.children, level + 1, false))
    }
    return sb.toString()
}