Sort Array of 0s, 1s, and 2s (Dutch National Flag)?

Short answer: void SortColors(int[] nums) {

Example code

int low = 0, mid = 0, high = nums.Length - 1; while (mid <= high) {
if (nums[mid] == 0)
(nums[low++], nums[mid++]) = (nums[mid], nums[low]); else if (nums[mid] == 1) mid++; else (nums[mid], nums[high--]) = (nums[high], nums[mid]);
}
} Follow on: Explanation: Partition array into three parts in one pass using three pointers.

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.