You are given an array of integers nums of size 3.
Return the maximum possible number whose binary representation can be formed by concatenating the binary representation of all elements in nums in some order.
Note that the binary representation of any number does not contain leading zeros.
Example 1:
Input:nums = [1,2,3]
Output: 30
Explanation:
Concatenate the numbers in the order [3, 1, 2] to get the result "11110", which is the binary representation of 30.
Example 2:
Input:nums = [2,8,16]
Output: 1296
Explanation:
Concatenate the numbers in the order [2, 8, 16] to get the result "10100010000", which is the binary representation of 1296.
Constraints:
nums.length == 3
1 <= nums[i] <= 127
Solutions
Solution 1: Enumeration
According to the problem description, the length of the array $\textit{nums}$ is $3$. We can enumerate all permutations of $\textit{nums}$, which has $3! = 6$ permutations. Then, we convert the elements of the permuted array into binary strings, concatenate these binary strings, and finally convert the concatenated binary string into a decimal number to get the maximum value.
The time complexity is $O(\log M)$, where $M$ represents the maximum value of the elements in $\textit{nums}$. The space complexity is $O(1)$.