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Problem

Submissions

Set K Bits

Last Updated: 23 Feb, 2023

Easy

0/40

Avg time to solve 10 mins

Success Rate 85 %

4 upvotes

Problem Statement

Given a number ‘N’. You have to set bits from 0 to Kth position.

Example: If the Given number is 37 (100101) and ‘K’ = 4, then we need to set the 0,1,2,3 bits and thus after the Kth bit set our answer would be 47 (101111).

Detailed explanation ( Input/output format, Notes, Images )

Input Format:

The first line contains a single integer ‘T’ representing the number of test cases. 

The first line of each test case will contain two integers ‘N’ and ‘K’ where ‘N’ denotes the number whose 0 to ‘K’th bits have to be set and ‘K’ indicates the limit upto where from 0th bit, the bits have to be set.

Output Format:

For each test case, print the number after 0 to Kth bits are set.

Output for every test case will be printed in a separate line.

Note:

You don’t need to print anything; It has already been taken care of.

Follow Up:

 Can you solve this using O(1) time and space complexity?

Constraints:

1 <= T <= 10
-10^9 <= N <= 10^9
1 <= K <= 31


Time limit: 1 sec

Sample Input 1:

2
5 2
16 3

Sample Output 1:

7
23

Explanation For Sample Input 1:

In the first test case, we have the number ‘N’ as 5 (101) and K=2. Thus after set 2 bits from the right, the answer will be 7 (111).

In the second test case, we have the number ‘N’ as 16 (10000) and K=3. Thus after set 3 bit from right, the answer will be 23 (10111).

Sample Input 2:

2
10 1
34 4

Sample Output 2:

11
47

Explanation For Sample Input 2:

In the first test case, we have the number ‘N’ as 10 (1010) and K=1. Thus after set 1 bit from right, the answer will be 11 (1011).

In the second test case, we have the number ‘N’ as 32 (100010) and K=4. Thus after set 3 bit from the right, the answer will be 47 (101111).

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