[Solution] Adjacent Xors CodeChef Solution

Problem

JJ has an array $A$ of length $N$ and an integer $X$. JJ can perform the following operation at most once:

• Select a subsequence of $A$ and add $X$ to all the elements of that subsequence.

For example, if $A = [2, 1, 6, 3, 5]$ and $X = 7$, we can select the subsequence $[2, 3, 5]$ and add $X$ to all the elements. Now the array $A$ becomes $[2 + 7, 1, 6, 3 + 7, 5 + 7] = [9, 1, 6, 10, 12]$.

JJ wants to maximize the value of $\displaystyle \sum_{i = 2}^{n} (A_{i - 1} \oplus A_{i})$. Can you help him to do so?

Here, $\oplus$ denotes the bitwise XOR operation.

Input Format

• The first line contains a single integer $T$ — the number of test cases. Then the test cases follow.

Solution Click Below:-  👉CLICK HERE👈

👇👇👇👇👇

• The first line of each test case contains two space-separated integers $N$ and $X$ — the size of the array $A$ and the parameter $X$ mentioned in the statement.
• The second line of each test case contains $N$ space-separated integers $A_1, A_2, \ldots, A_N$ denoting the array $A$.

Output Format

For each test case, output the maximum value of $\displaystyle \sum_{i = 2}^{n} (A_{i - 1} \oplus A_{i})$ which can be obtained after applying the given operation at most once.

Explanation:

Test case $1$: It is optimal to not perform the given operation. So the answer will equal $1 \oplus 2 = 3$.

Test case $2$: It is optimal to add $X = 1$ to the $2^{nd}$ and the $3^{rd}$ element. So $A$ will become $[2, 3, 4, 3]$ and the answer will be $(2 \oplus 3) + (3 \oplus 4) + (4 \oplus 3) = 15$.