https://www.luogu.com.cn/record/125996361

#include <iostream>
using namespace std;

int n, val[260], winner[260];

void dfs(int x)
{
    if (x > 1 << n)
        return;
    dfs(2 * x);
    dfs(2 * x + 1);
    if (val[winner[2 * x]] > val[winner[2 * x + 1]])
        winner[x] = winner[2 * x];
    else
        winner[x] = winner[2 * x + 1];
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    cin >> n;
    for (int i = 1; i <= 1 << n; i++)
    {
        cin >> val[i];
        winner[(1 << n) + i] = i;
    }
    dfs(1);
    cout << (val[winner[2]] > val[winner[3]] ? winner[3] : winner[2]) << "\n";
    return 0;
}