# Generating Permutations Multiple choice Questions and Answers (MCQs)

## Click on any option to know the CORRECT ANSWERS

 Question 1
The dictionary ordering of elements is known as?
 A Lexicographical order B Colexicographical order C Well order D Sorting

Question 1 Explanation:
Lexicographical order is also known as dictionary order. It is a generalized method of the way words are alphabetically ordered in a dictionary.

 Question 2
How many permutations will be formed from the array arr={1, 2, 3}?
 A 2 B 4 C 6 D 8

Question 2 Explanation:
No.of permutations for an array of size n will be given by the formula nPn. So for the given problem, we have 3P3=6 or 3!=6.

 Question 3
What will be the lexicographical order of permutations formed from the array arr={1, 2, 3}?
 A {{2, 1, 3}, {3, 2, 1}, {3, 1, 2}, {2, 3, 1}, {1, 2, 3}, {1, 3, 2}} B {{1, 2, 3}, {1, 3, 2}, {2, 3, 1}, {2, 1, 3}, {3, 2, 1}, {3, 1, 2}} C {{1, 2, 3}, {1, 3, 2}, {2, 1, 3}, {2, 3, 1}, {3, 1, 2}, {3, 2, 1}} D {{2, 1, 3}, {3, 1, 2}, {3, 2, 1}, {2, 3, 1}, {1, 2, 3}, {1, 3, 2}}

Question 3 Explanation:
The number of permutations for the problem will be 6 according to the formula 3P3. When ordered in lexicographical manner these will be {{1, 2, 3}, {1, 3, 2}, {2, 1, 3}, {2, 3, 1}, {3, 1, 2}, {3, 2, 1}}.

 Question 4
What is the name given to the algorithm depicted in the pseudo code below?

procedure generate(n : integer,  Arr : array): if n = 1 then output(Arr) else for i = 0; i <= n - 2; i ++ do generate(n - 1,  Arr) if n is even then swap(Arr[i],  Arr[n-1]) else swap(Arr,  Arr[n-1]) end if end for generate(n - 1,  Arr ) end if
 A bubble sort B heap sort C heap's algorithm D Prim's algorithm

Question 4 Explanation:
The given algorithm is called Heap's algorithm. It is used for generating permutations of a given list.

 Question 5
Heap's algorithm requires an auxiliary array to create permutations.
 A true B false

Question 5 Explanation:
Heap's algorithm does not require any extra array for generating permutations. Thus it is able to keep its space requirement to a very low level. This makes it preferable algorithm for generating permutations.

There are 5 questions to complete.