Given 3 integers N, L and R. The task is to construct an array A[] of N integers, such that :
 Each element of the array is in the range [L, R].
 GCD(i, A[i]) are distinct for all elements.
Examples :
Input : N = 5, L = 1, R = 5
Output : {1, 2, 3, 4, 5}
Explanation : It can be seen that each element is in the range [1, 5].
Also, for i = 1, GCD(1, 1)=1, for i = 2, GCD(2, 2) = 2, for i = 3,
GCD(3, 3) = 3, for i = 4, GCD(4, 4) = 4 and for i = 5, GCD(5, 5) = 5.
Hence, all of these are distinct.Input : N = 10, L = 30, R = 35
Output : 1
Explanation : It is not possible to construct an array
satisfying the given conditions.
Approach: The approach of the problem is based on the following observation
To satisfy the given conditions, we will have to assure GCD(i, A[i]) = i, for each index of the array from 1 to N.
The idea is to find the smallest possible element with gcd(i, A[i]) = i, larger than or equal to L for each i, and if that element is smaller than equal to R, then we append it, otherwise we return 1(means not possible).
The problem can be solved by the following approach:
 Iterate from i = 1 to N.
 For each i, find the minimum multiple of i that is strictly greater than L − 1.
 Check if that multiple is less than or equal to R.
 If so, that multiple would be the i^{th} element of the array.
 Else, array construction would not be possible.
Below is the implementation of the above approach:
C++

Time Complexity: O(N)
Auxiliary Space: O(N)