I recently encountered this problem in an Interview.
You are given N. You have to construct an array of 2*N size with conditions:
You have to use a number from 1 to N that means each number must be used exactly twice.
Distance between indices of the same number should be equal to (number + 1).
The output should be true if the construction of such an array is possible else it should be false.
EG: Input 3 Output true
Explanation: possible array is [2, 3, 1, 2, 1, 3]
Note: The bounds on N were not given in the question.
Can anybody help me with this?