Algorithm
Hacker rank Problem Name: 10 Days of JavaScript -
Hacker rank Problem Link: https://www.hackerrank.com/challenges/js10-bitwise/problem?isFullScreen=true
Day 6: Bitwise Operators
Objective
Today, we’re practicing bitwise operations. Check the attached tutorial for more details.
Task
We define S to be a sequence of distinct sequential integers from 1 to n; in other words, S = {1,2,3,…,n}. We want to know the maximum bitwise AND value of any two integers, a and b (where (a < b)), in sequence S that is also less than a given integer, k.
Complete the function in the editor so that given n and k, it returns the maximum a & b < k.
Note: The & symbol represents the bitwise AND operator.
Input Format
The first line contains an integer, q, denoting the number of function calls.
Each of the q subsequent lines defines a dataset for a function call in the form of two space-separated integers describing the respective values of n and k.
Constraints
- 1 <= q <= 10^3
- 2 <= n <= 10^3
- 2 <= k <= n
Output Format
Return the maximum possible value of a & b < k for any a < b in sequence S.
Sample Input 0
1 |
3 |
Sample Output 0
1 |
1 |
Explanation 0
We perform the following q = 3 function calls:
- When n = 5 and k = 2, we have the following possible a and b values in set S = {1,2,3,4,5}:
a | b | a & b |
---|---|---|
1 | 2 | 001 & 010 = (000)^2 => (0) |
1 | 3 | 001 & 011 = (001)^2 => (1) |
1 | 4 | 001 & 100 = (000)^2 => (0) |
1 | 5 | 001 & 101 = (001)^2 => (1) |
2 | 3 | 010 & 011 = (010)^2 => (2) |
2 | 4 | 010 & 100 = (000)^2 => (0) |
2 | 5 | 010 & 101 = (000)^2 => (0) |
3 | 4 | 011 & 100 = (000)^2 => (0) |
3 | 5 | 011 & 101 = (001)^2 => (1) |
4 | 5 | 100 & 101 = (100)^2 => (4) |
- The maximum of any a & b that is also < k is 1, so we return 1.
- When n = 8 and k = 5, the maximum of any a & b < k in set S = {1,2,3,4,5,6,7,8} is 4 (see table above), so we return 4.
- When n = 2 and k = 2, the maximum of any a & b < k in set S = {1,2} is 0 (see table above), so we return 0.
Sample Input 1
1 |
2 |
Sample Output 1
1 |
1 |
Explanation 1
We perform the following q = 2 function calls:
- When n = 9 and k = 2, we have the following possible a and b values in set S = {1,2,3,4,5,6,7,8,9}** is 1 (see table above), so we return 1.
- When n = 8 and k = 3, the maximum of any a & b < k in set S = {1,2,3,4,5,6,7,8} is 2 (see table above), so we return 2.
Code Examples
#1 Code Example with Javascript Programming
Code -
Javascript Programming
'use strict';
process.stdin.resume();
process.stdin.setEncoding('utf-8');
let inputString = '';
let currentLine = 0;
process.stdin.on('data', inputStdin => {
inputString += inputStdin;
});
process.stdin.on('end', _ => {
inputString = inputString.trim().split('\n').map(string => {
return string.trim();
});
main();
});
function readLine() {
return inputString[currentLine++];
}
function getMaxLessThanK(n, k) {
var mx = -1;
for(var i=1; i < =n; i++){
for(var j=i+1; j < =n; j++){
var res = i & j;
if(res > mx && res < k>{
mx = res;
}
}
}
return mx;
};
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Input
Output