Day29 Bitwise AND

Objective

Welcome to the last day! Today, we’re discussing bitwise operations. Check out the Tutorial tab for learning materials and an instructional video!

Task

Given set . Find two integers, A and B (where A < B ), from set S such that the value of A & B is the maximum possible and also less than a given integer, K.
In this case, & represents the bitwise AND operator.

Input Format

The first line contains an integer, T, the number of test cases.
Each of the T subsequent lines defines a test case as 2 space-separated integers, N and K, respectively.

Constraints

Output Format

For each test case, print the maximum possible value of on a new line.

Sample Input

1
2
3
4

3
5 2
8 5
2 2

Sample Output

1
2
3

1
4
0

Explanation

All possible values of and are:

The maximum possible value of A&B that is also < (K = 2) is 1, so we print 1 on a new line.

Solution

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

function findMax(n, k) {
    var max = 0;
    for (let i = 0; i <= n; i++) {
        for (let j = 0; j < i; j++) {
            let value = j & i;
            if (value < k && value > max) {
                max = value;
            }
        }
    }

    return max;
}

function main() {
    const t = parseInt(readLine(), 10);

    for (let tItr = 0; tItr < t; tItr++) {
        const nk = readLine().split(' ');

        const n = parseInt(nk[0], 10);

        const k = parseInt(nk[1], 10);

        console.log(findMax(n, k));
    }
}