1823-find-the-winner-of-the-circular-game.java

class Solution {
    public int findTheWinner(int n, int k) {
        return solve(n, k) + 1;
    }

    private int solve(int n, int k) {
        if (n == 1)
            return 0;
        return (solve(n - 1, k) + k) % n;
    }
}