2401. Longest Nice Subarray

2401. Longest Nice Subarray
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You are given an array nums consisting of positive integers.

We call a subarray of nums nice if the bitwise AND of every pair of elements that are in different positions in the subarray is equal to 0.

Return the length of the longest nice subarray.

A subarray is a contiguous part of an array.

Note that subarrays of length 1 are always considered nice.

 

Example 1:

Input: nums = [1,3,8,48,10]
Output: 3
Explanation: The longest nice subarray is [3,8,48]. This subarray satisfies the conditions:
- 3 AND 8 = 0.
- 3 AND 48 = 0.
- 8 AND 48 = 0.
It can be proven that no longer nice subarray can be obtained, so we return 3.
Example 2:

Input: nums = [3,1,5,11,13]
Output: 1
Explanation: The length of the longest nice subarray is 1. Any subarray of length 1 can be chosen.
 

Constraints:

1 <= nums.length <= 105
1 <= nums[i] <= 109
class Solution {

    public int longestNiceSubarray(int[] nums) {
        int usedBits = 0; // Tracks bits used in current window
        int windowStart = 0; // Start position of current window
        int maxLength = 0; // Length of longest nice subarray found

        for (int windowEnd = 0; windowEnd < nums.length; ++windowEnd) {
            // If current number shares bits with window, shrink window from left
            // until there's no bit conflict
            while ((usedBits & nums[windowEnd]) != 0) {
                usedBits ^= nums[windowStart]; // Remove leftmost element's bits
                windowStart++;
            }

            // Add current number to the window
            usedBits |= nums[windowEnd];

            // Update max length if current window is longer
            maxLength = Math.max(maxLength, windowEnd - windowStart + 1);
        }

        return maxLength;
    }
}