Rockethon 2015

b2.cpp

#include <bits/stdc++.h>
 
#define all(v) v.begin(),v.end()

using namespace std;
using ll = long long;

int main()
{
    int n;
    ll m;
    cin >> n >> m;
    vector<int> head, tail;
    for (int i = 1; i < n; i++) {
        if (m <= (1ll << n-i-1)) {
            head.push_back(i);
        } else {
            tail.push_back(i);
            m -= (1ll << n-i-1);
        }
    }
    head.push_back(n);

    for (int v : head) cout << v << " ";
    reverse(all(tail));
    for (int v : tail) cout << v << " ";
    cout << endl;
    return 0;
}

c.cpp

#include <bits/stdc++.h>
 
#define loop(n, i) for(int i=0;i<n;i++)

using namespace std;

int main()
{
    int n; cin >> n;
    vector<int> l(n), r(n);
    loop (n, i) cin >> l[i] >> r[i];
    double ans = 0;

    loop (n, snd) for (int v = l[snd]; v <= r[snd]; v++) {
        loop (n, fst) if (fst != snd) {
            double prod = 1.0 / (r[snd] - l[snd] + 1);

            loop (n, i) if (i != snd) {
                // Pr(price[i] < v)  for i < snd
                // Pr(price[i] <= v) for i > snd
                int right = min(r[i], v - (i < snd));
                double x = max(right - l[i] + 1, 0);
                double p_lt = x / (r[i] - l[i] + 1);
                prod *= (i == fst ? 1.0 - p_lt : p_lt);
            }

            ans += prod * v;
        }
    }
    printf("%.12f\n", ans);
    return 0;
}