Submission #429252

#	Time	Username	Problem	Language	Result	Execution time	Memory
429252		Tangent	Roller Coaster Railroad (IOI16_railroad)	C++17	11 / 100	2076 ms	9636 KiB

railroad

#include "railroad.h"
#include "bits/stdc++.h"

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vii;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<vii> vvii;
typedef vector<vll> vvll;
typedef vector<vpii> vvpii;
typedef vector<vpll> vvpll;

#define ffor(i, a, b) for (ll i = (a); i < (ll)(b); i++)
#define fford(i, a, b) for (ll i = (a); i > (ll)(b); i--)
#define rep(i, n) ffor(i, 0, n)
#define forin(x, a) for (auto &x: a)
#define all(a) a.begin(), a.end()

#define cost(a, b) max(0, t[a] - s[b])
#define ocost(a, b) cost(order[a], order[b])

long long plan_roller_coaster(std::vector<int> s, std::vector<int> t) {
    int n = (int) s.size();

    ll res = 1LL << 62;

    vii used(n);
    ll curr = 0;
    vii order;

    function<void(int)> dfs;
    dfs = [&](int p) {
        if (curr > res) {
            return;
        }
        if ((int)order.size() == n) {
            res = min(res, curr);
            return;
        }
        int speed;
        if (p == -1) {
            speed = 1;
        } else {
            speed = t[p];
        }
        rep(i, n) {
            if (used[i]) {   
                continue;
            }
            if (order.size() == 2 && ocost(0, 1) + cost(order[1], i) > ocost(1, 0) + cost(order[0], i)) {
                continue;
            }
            if (order.size() > 2 && ocost(order.size() - 3, order.size() - 2) + ocost(order.size() - 2, order.size() - 1)  + cost(order.back(), i) > ocost(order.size() - 3, order.size() - 1) + ocost(order.size() - 1, order.size() - 2)  + cost(order[order.size() - 2], i)) {
                continue;
            }
            used[i] = true;
            curr += max(0, speed - s[i]);
            order.emplace_back(i);
            dfs(i);
            order.pop_back();
            curr -= max(0, speed - s[i]);
            used[i] = false;
        }
    };
    dfs(-1);

    return res;
}

• Subtask 1: 11 / 11
• Subtask 2: 0 / 23
• Subtask 3: 0 / 30
• Subtask 4: 0 / 36