A marketing banner is a strip n units wide. A designer fills it from left to right with tiles that are 1, 2, or 3 units wide, with no gaps and no overlap. The order matters: a 1-unit tile followed by a 2-unit tile is a different layout from a 2 followed by a 1.
Write countTilings(n) that returns the number of different layouts that fill the strip exactly. An empty strip (n = 0) has exactly one layout: no tiles.
Input: n = 3 Output: 4
1+1+1, 1+2, 2+1, and 3.
Input: n = 4 Output: 7
Layouts ending with a 1 (4 of them), a 2 (2 of them), or a 3 (1 of them).
0 <= n <= 35Run tries your code on the examples. Submit runs every test, including hidden edge cases, and solves the problem when they all pass.
Ctrl + Enter runs, Ctrl + Shift + Enter submits (⌘ on a Mac).
I'm here to help with #484 Tile a Banner Strip. I give hints, never the solution, so you get to solve it yourself. Ask for a hint, select code to ask about it, or press Ask Tuto why on a failing test.
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