Welcome to Weekly Contest 249! Feel free to share and post your contest experience here!

You can also view the rankings for the contest here.

Links to the individual problems are included below:

Concatenation of Array (3 points)

Unique Length-3 Palindromic Subsequences (4 points)

Painting a Grid With Three Different Colors (6 points)

Merge BSTs to Create Single BST (6 points)