Submission #617072

#	Time	Username	Problem	Language	Result	Execution time	Memory
617072		Zanite	Roller Coaster Railroad (IOI16_railroad)	C++17	34 / 100	71 ms	34852 KiB

railroad

#include "railroad.h"

#include <bits/stdc++.h>
using namespace std;

using ll	= long long;

const ll maxN	= 17;
const ll maxM	= (1 << 16) + 5;
const ll INF	= 1e18;

ll n;
vector<ll> S, T;
ll memo[maxM][maxN];

ll dp(ll mask, ll cur) {
	if (__builtin_popcountll(mask) == 1) {return 0;}
	else if (memo[mask][cur] != -1) {return memo[mask][cur];}

	ll ret = INF;
	ll prv = mask ^ (1ll << cur);
	for (ll b = 0; b < n; b++) {
		if (prv & (1ll << b)) {
			ret = min(ret, dp(prv, b) + max(0ll, T[b] - S[cur]));
		}
	}

	//printf("memo[%lld][%lld] = %lld\n", mask, cur, ret);
	return memo[mask][cur] = ret;
}

ll plan_roller_coaster(vector<int> s, vector<int> t) {
	n = s.size();
	ll maxMask = (1 << n) - 1;

	for (auto i : s) {S.push_back(i);}
	for (auto i : t) {T.push_back(i);}

	for (ll i = 0; i < n; i++) {
		for (ll mask = 0; mask <= maxMask; mask++) {
			memo[mask][i] = -1;
		}
	}

	ll ans = INF;
	for (ll i = 0; i < n; i++) {
		ans = min(ans, dp(maxMask, i));
	}
	return ans;
}

#ifdef Zanite
int main() {
    int n;
    assert(1 == scanf("%d", &n));
    std::vector<int> s(n), t(n);
    for (int i = 0; i < n; ++i)
        assert(2 == scanf("%d%d", &s[i], &t[i]));
    long long ans = plan_roller_coaster(s, t);
    printf("%lld\n", ans);
    return 0;
}
#endif

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