Picat Data Structures and Types Questions and Answers

Question 1

A developer needs to store student IDs (integers) as keys and their corresponding grades (strings) as values, with frequent lookups.
Which Picat code snippet correctly creates a map, adds a student's grade, and retrieves it?

Accepted Answer

import util.
M = new_map(), M.put(101, "A"), Grade = M.get(101)

Answer

M = [101:"A"], Grade = M[101]

Answer

M = student(101, "A"), Grade = M.2

Answer

M = new_map(), M[101] := "A", Grade = M[101]

Question 2

Given the Picat list `L = [a, b, c, d]`, which unification will successfully bind the variable `H` to the atom `a` and the variable `T` to the list `[b, c, d]`?

Accepted Answer

[H | T] = L

Answer

L = H :: T

Answer

[H, T] = L

Answer

H = L[1], T = L[2..4]

Question 3

You are designing a system to represent a simple family tree. You need to store a person's name, year of birth, and a list of their children (who are also people). Which data structure is most idiomatic and efficient for representing a single person with these fixed fields?

Accepted Answer

A structure like `$person(Name, YearOfBirth, ChildrenList)`

Answer

A list like `[Name, YearOfBirth, ChildrenList]`

Answer

An array

Answer

A map where keys are `"name"`, `"yob"`, and `"children"`

Question 4

Which of the following statements correctly identifies the data type of the Picat term `'hello world'`?

Accepted Answer

It is an atom.

Answer

It is a string, which is a list of characters.

Answer

It is a variable.

Answer

It is a list containing two atoms, `hello` and `world`.

Question 5

What is the result of the unification `$point(X, Y) = $point(10, 20)` in Picat?

Accepted Answer

X is unified with `10`, and Y is unified with `20`.

Answer

The unification fails because structures cannot be unified directly.

Answer

A syntax error occurs.

Answer

X is unified with `$point(10, 20)` and Y remains unbound.

Question 6

What is the fundamental difference between `L1 = ["a", "b"]` and `L2 = [a, b]` in Picat?

Accepted Answer

`L1` is a list of strings, while `L2` is a list of atoms.

Answer

There is no difference; they are syntactically equivalent.

Answer

`L1` is a valid list, but `L2` will cause a syntax error.

Answer

`L1` is a list of variables, while `L2` is a list of atoms.

A developer needs to store student IDs (integers) as keys and their corresponding grades (strings) as values, with frequent lookups.Which Picat code snippet correctly creates a map, adds a student's grade, and retrieves it?

A developer needs to store student IDs (integers) as keys and their corresponding grades (strings) as values, with frequent lookups.
Which Picat code snippet correctly creates a map, adds a student's grade, and retrieves it?