Description
You are given an array nums consisting of n prime integers.
You need to construct an array ans of length n, such that, for each index i, the bitwise OR of ans[i] and ans[i] + 1 is equal to nums[i], i.e. ans[i] OR (ans[i] + 1) == nums[i].
Additionally, you must minimize each value of ans[i] in the resulting array.
If it is not possible to find such a value for ans[i] that satisfies the condition, then set ans[i] = -1.
Example 1:
Input: nums = [2,3,5,7]
Output: [-1,1,4,3]
Explanation:
- For
i = 0, as there is no value forans[0]that satisfiesans[0] OR (ans[0] + 1) = 2, soans[0] = -1. - For
i = 1, the smallestans[1]that satisfiesans[1] OR (ans[1] + 1) = 3is1, because1 OR (1 + 1) = 3. - For
i = 2, the smallestans[2]that satisfiesans[2] OR (ans[2] + 1) = 5is4, because4 OR (4 + 1) = 5. - For
i = 3, the smallestans[3]that satisfiesans[3] OR (ans[3] + 1) = 7is3, because3 OR (3 + 1) = 7.
Example 2:
Input: nums = [11,13,31]
Output: [9,12,15]
Explanation:
- For
i = 0, the smallestans[0]that satisfiesans[0] OR (ans[0] + 1) = 11is9, because9 OR (9 + 1) = 11. - For
i = 1, the smallestans[1]that satisfiesans[1] OR (ans[1] + 1) = 13is12, because12 OR (12 + 1) = 13. - For
i = 2, the smallestans[2]that satisfiesans[2] OR (ans[2] + 1) = 31is15, because15 OR (15 + 1) = 31.
Constraints:
1 <= nums.length <= 1002 <= nums[i] <= 1000nums[i]is a prime number.
Solutions
This function finds the minimum bitwise value for each number in the input array. For each number num, it searches for the smallest value i (starting from 1) where the bitwise OR of i and i + 1 equals num—if such a value exists, it returns i; otherwise it returns -1. For example, if num is 3, the function checks 1 | 2 = 3, which is true, so it returns 1. The algorithm iterates through each potential value and uses the bitwise OR operator (|) to combine adjacent numbers until it finds a match, then moves to the next number in the input array and repeats the process.
/**
* @param {number[]} nums
* @return {number[]}
*/
var minBitwiseArray = function (nums) {
const res = [];
for (const num of nums) {
let cur = -1;
for (let i = 1; i < num; i++) {
if ((i | (i + 1)) === num) {
cur = i;
break;
}
}
res.push(cur);
}
return res;
};