public class Main {
 
    static int unique(int[] a) {
        int left = 0, right = a.length - 1;
 
        while (left < right) {
            int mid = (left + right) / 2;
            boolean even = (mid % 2 == 0);
 
            if (even) {
                if (a[mid] == a[mid + 1]) left = mid + 2;
                else right = mid;
            } else {
                if (a[mid] == a[mid - 1]) left = mid + 1;
                else right = mid - 1;
            }
        }
 
        return a[left];
    }
 
    public static void main(String[] args) {
        int[] nums = {1, 1, 4, 4, 7, 8, 8};
        System.out.println(unique(nums));
    }
}
 

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