Find Element that Appears Once in Sorted Array?

Short answer: (Others Appear Twice) int SingleNonDuplicate(int[] nums)

Example code

{
int low = 0, high = nums.Length - 1; while (low < high) {
int mid = low + (high - low) / 2;
if (mid % 2 == 1) mid--; // ensure mid is even
if (nums[mid] == nums[mid + 1])
low = mid + 2; else high = mid; Follow on: }
return nums[low];
} Explanation: Pairs appear consecutively; use binary search on even indices to find mismatch.

Real-world example (ShopNest)

In coding rounds, state complexity aloud, write a clear ShopNest-flavored example (orders, carts), then handle edge cases (empty list, null, overflow).

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.