Submission #711228

#	Time	Username	Problem	Language	Result	Execution time	Memory
711228		Nhoksocqt1	Boxes with souvenirs (IOI15_boxes)	C++17	10 / 100	1 ms	316 KiB

boxes

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

#define inf 0x3f3f3f3f
#define sz(x) int((x).size())
#define fi first
#define se second
typedef long long ll;
typedef pair<int, int> ii;

template<class X, class Y>
	inline bool maximize(X &x, const Y &y) {return (x < y ? x = y, 1 : 0);}
template<class X, class Y>
	inline bool minimize(X &x, const Y &y) {return (x > y ? x = y, 1 : 0);}

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int Random(int l, int r) {
    return uniform_int_distribution<int>(l, r)(rng);
}

const int MAXN = 1e7+7;

int a[MAXN], nArr, k, L;

#ifdef Nhoksocqt1

ll delivery(int _N, int _K, int _L, int _pos[]);

int _P[MAXN];

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    freopen("BOXES.inp", "r", stdin);
    freopen("BOXES.out", "w", stdout);

    int N, K, L;
    cin >> N >> K >> L;

    for (int i = 0; i < N; ++i) {
        cin >> _P[i];
    }

    cout << delivery(N, K, L, _P) << '\n';
    return 0;
}

#endif // Nhoksocqt1

ll delivery(int _N, int _K, int _L, int _pos[]) {
    nArr = _N, k = _K, L = _L;
    for (int i = 1; i <= nArr; ++i)
        a[i] = _pos[i - 1];

    ll result(0);
    int l(1), r(nArr);
    for (int i = 1; i <= nArr; ++i) {
        if(2 * a[i] >= L)
            break;

        if(i % k == 0) {
            result += 2 * a[i];
            l = i + 1;
        }
    }

    for (int i = nArr; i >= l; --i) {
        if(2 * (L - a[i]) >= L)
            break;

        if((nArr - i + 1) % k == 0) {
            result += 2 * (L - a[i]);
            r = i - 1;
        }
    }

    ll answer(1e18);
    int last = min(k, r - l + 1);
    for (int dem = 0; dem <= last; ++dem) {
        int costLeft = (dem > 0 ? min(L, 2 * a[l + dem - 1]) : 0);
        ll costRight = (dem <= r - l ? 1LL * (r - l + 1 - dem + k - 1) / k * L : 0LL);
        answer = min(answer, result + costLeft + costRight);
    }

    return answer;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30