Longest Increasing Subsequence (LIS)?

Short answer: int LIS(int[] nums) { int n = nums.Length; int[] dp = new int[n]; Array.Fill(dp, 1); int maxLen = 1; for (int i = 1; i < n; i++) { for (int j = 0; j < i; j++) { if (nums[i] > nums[j]) dp[i] = Math.Max(dp[i], dp[j] + 1); } maxLen = Math.Max(maxLen, dp[i]); } return maxLen; } Explanation: For each element, find LIS ending there by checking previous smaller elements. Follow on:

Example code

int LIS(int[] nums)
{
int n = nums.Length;
int[] dp = new int[n]; Array.Fill(dp, 1); int maxLen = 1;
for (int i = 1; i < n; i++)
{
for (int j = 0; j < i; j++)
{
if (nums[i] > nums[j])
dp[i] = Math.Max(dp[i], dp[j] + 1);
}
maxLen = Math.Max(maxLen, dp[i]);
}
return maxLen;
} Explanation: For each element, find LIS ending there by checking previous smaller elements. Follow on:

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.