3133. Minimum Array End

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You are given two integers n and x. You have to construct an array of positive integers nums of size n where for every 0 <= i < n - 1, nums[i + 1] is greater than nums[i], and the result of the bitwise AND operation between all elements of nums is x.

Return the minimum possible value of nums[n - 1].

 

Example 1:

Input: n = 3, x = 4

Output: 6

Explanation:

nums can be [4,5,6] and its last element is 6.

Example 2:

Input: n = 2, x = 7

Output: 15

Explanation:

nums can be [7,15] and its last element is 15.

 

Constraints:

  • 1 <= n, x <= 108

Hints

Hint 1
Each element of the array should be obtained by “merging” x and v where v = 0, 1, 2, …(n - 1).
Hint 2
To merge x with another number v, keep the set bits of x untouched, for all the other bits, fill the set bits of v from right to left in order one by one.
Hint 3
So the final answer is the “merge” of x and n - 1.