Berlin 2024 CODE100 Quiz and Knowledge rounds

Pseudo Code Quiz Round

These rounds are run on Slido and challengers need to pick an answer on their phones. This means both understanding the question and speed are of the essence.

1. This function runs for each item in an array, [4, 6, 8, 7]. Which number will return true?

    Function OPTIMUS(num)
        For each number i from 2 to sqrt(num)
            If num is divisible by i then
                Return false
            End If
        End For
        Return true
    End Function
   

   Question options

   • 4
   • 6
   • 8
   • 7 (correct answer)

   This function will iterate over numbers in an array, and check if the number is a prime number. In this example, 7 is a prime number so will return true. See the prime number CodePen.

   (The optimus name was a giveaway…)

2. Select the ‘nums’ input that will return ‘HUNDRED’.

    Function convertNumbersToWord(nums)
        Set alphabet to "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        Set result to an empty string
        For each num in nums
            If (num is greater than or equal to 1) and 
            (num is less than or equal to 26) then
                Append alphabet[num - 1] to result
            Else
                Return "Invalid number in input"
        End For
        Return result
    End Function
   

   Question options

   • [7, 20, 13, 3, 17, 4, 3]
   • [8, 21, 14, 4, 18, 5, 4] (correct)
   • [6, 19, 12, 2, 16, 3, 2]
   • [9, 22, 15, 5, 19, 6, 5]

   Notes: The correct answer is [8, 21, 14, 4, 18, 5, 4]. H is the 8th item in the alphabet string, but there is a -1 in there… See the one hundred CodePen.

3. Based on the function below, which pair of strings will return true?

    Function checkDatesDistance(date1, date2)
        diffTime = absolute difference in time 
                between date1 and date2    
        diffDays = convert diffTime to days    
        If diffDays equals 100 then
            Return true
        Else
            Return false
        End If
    End Function
   

   Question options:

   • new Date(“2024-04-08”), new Date(“2024-06-09”) (correct)
   • new Date(“2024-02-01”), new Date(“2024-02-02”)
   • new Date(“2024-01-01”), new Date(“2024-01-30”)
   • new Date(“2024-02-01”), new Date(“2024-12-31”)

   Notes: The first option is correct as the two dates are 100 days apart. See the 100 days CodePen.

4. If numbers is [9, 50, 27, 49], then which one will be returned by the function?

    Function findMatchingMultiple(numbers)
        For i from 1 to infinity
            For each number in numbers
                product = i * number
                If product equals 100 then
                    Return number
                End If
            End For
        End For
        Return false
    End Function
   

   Question options:

   • 9
   • 50 (correct answer)
   • 99
   • 72

   Notes: This counts from 1, and multiplies this number by each item in the array. If the result is 100, it should return the number from the array, ie: 50 (* 2). See the double codepen.

5. Based on the function below, which year will return 6?

   ```lisp Function calculateCenturiesPassed(year) Set currentYear to 2024 diffYears = difference in years between currentYear and year centuriesPassed = diffYears / 100 centuriesPassed = roundDown(centuriesPassed) Return centuriesPassed End Function

   Question options:

   • 1824
   • 1948
   • 1736
   • 1366 (correct)

   Notes : This function takes an input, year, and calculates how many centuries have passed between year and 2024, and return the number.

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