Калькулятор/перебор

// 26 points Calculator region first tour 16-17 https://informatics.mccme.ru/mod/statements/view3.php?id=24702&chapterid=113440#

# include <iostream>

using namespace std;

void search(size_t n, size_t a, size_t b, size_t c, size_t &max_ans) {
    if ((a + b + c) == 0 || n == 0) {
        max_ans = min(max_ans, n);
    } else {
        if (a > 0) {
            search(n / 2, a - 1, b, c, max_ans);
        }
        if (b > 0) {
            search((n + 1) / 2, a, b - 1, c, max_ans);
        }
        if (c > 0) {
            search(max(static_cast<size_t> (0), (n - 1) / 2), a, b, c - 1, max_ans);
        }
    }
}
int main() {
    size_t n, a, b, c;
    cin >> n >> a >> b >> c;
    size_t ans = n;
    search(n, a, b, c, ans);
    cout << ans;
    return 0;
}