Day 29: Bitwise AND
Problem
Objective
Hey CodingHumans Welcome to the last day! of HackerRank 30 days of code today, we're discussing bitwise operations.
Task
Given set S={1,2,3,4.....N} . Find two integers, A and B (where ), 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 Style
The first line contains an integer, T, the number of test cases.
Each of the T subsequent lines defines a test case as space-separated integers, N and K, respectively.
Constraints
1<= T <= 10^3
2<= N <=10^3
2<= K <=N
Output Style
For each test case, print the maximum possible value of A&B on a new line.
Sample Input
3
5 2
8 5
2 2
Sample Output
1
4
0
Explanation
N=5, K=2 S={1,2,3,4,5}
All possible values of A and B are:
1. A=1, B=2; A & B = 0
2. A=1, B=3; A & B = 1
3. A=1, B=4; A & B = 0
4. A=1, B=5; A & B = 1
5. A=2, B=3; A & B = 2
6. A=2, B=4; A & B = 0
7. A=2, B=5; A & B = 0
8. A=3, B=4; A & B = 0
9. A=3, B=5; A & B = 1
10. A=4, B=5; A & B = 4
The maximum possible value of A & B that is also <(K=2) is 1, so we print 1 on a new line.
Recommended: Please try your approach on your integrated development environment (IDE) first, before moving on to the solution.
Few words from CodingHumans : Don't Just copy paste the solution, try to analyze the problem and solve it without looking by taking the the solution as a hint or a reference . Your understanding of the solution matters.
HAPPY CODING 😁
Solution
( Java )
import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;
public class Solution {
private static final Scanner scanner = new Scanner(System.in);
public static void main(String[] args) {
int t = scanner.nextInt();
for (int tItr = 0; tItr < t; tItr++) {
int n = scanner.nextInt();
int k = scanner.nextInt();
int res=0;
for(int i=0;i<n;i++){
for(int j=i+1;j<=n;j++){
int and=i&j;
if(and<k && and > res){
res=and;
}
}
}
System.out.println(res);
}
scanner.close();
}
}
If you have any doubts regarding this problem or need the solution in other programming languages then leave a comment down below .
