<pre class="shiki github-dark shaku"><code>function canWinStonePicking(n: number): 'A' | 'B' | null { return n % 3 === 1 ? 'B' : 'A';}</code></pre>

Simple O(N)

Google

There is a pile of n (n > 0) stones. Player A and Player B take turns to pick 1 or 2 stones from the pile. A starts first. Who picks the last stone lo…