Submission #1269172

#	Time	Username	Problem	Language	Result	Execution time	Memory
1269172		phancddev	MP3 Player (CEOI10_mp3player)	C++20	60 / 100	31 ms	6472 KiB

mp3player

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

struct Node {
    int S, L, R;
};

int VMAX;

inline Node ident() { return {0, 0, VMAX}; }

inline Node leafFromOp(char c) { return {(c == '+') ? 1 : -1, 0, VMAX}; }

inline Node combine(const Node& left, const Node& right) {
    Node res;
    res.S = left.S + right.S;
    res.L = max(left.L + right.S, right.L);
    res.R = min(left.R + right.S, right.R);
    return res;
}

inline int clampInt(int x, int lo, int hi) {
    if (x < lo) return lo;
    if (x > hi) return hi;
    return x;
}

struct SegTree {
    int n;
    vector<Node> st;
    SegTree(int n_ = 0) { init(n_); }
    void init(int n_) {
        n = max(1, n_);
        st.assign(4 * n, ident());
    }
    void update(int idx, const Node& val, int p, int l, int r) {
        if (l == r) { st[p] = val; return; }
        int m = (l + r) >> 1;
        if (idx <= m) update(idx, val, p << 1, l, m);
        else update(idx, val, p << 1 | 1, m + 1, r);
        st[p] = combine(st[p << 1], st[p << 1 | 1]);
    }
    void update(int idx, const Node& val) { update(idx, val, 1, 0, n - 1); }
    Node all() const { return st[1]; }
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N, V2;
    if (!(cin >> N >> VMAX >> V2)) return 0;

    vector<char> op(N + 1);
    vector<int> t(N + 1);
    for (int i = 1; i <= N; ++i) cin >> op[i] >> t[i];

    if (N == 1) { cout << "infinity\n"; return 0; }

    vector<pair<int,int>> byDelta;
    byDelta.reserve(N - 1);
    for (int i = 2; i <= N; ++i)
        byDelta.emplace_back(t[i] - t[i - 1], i);
    sort(byDelta.begin(), byDelta.end());

    vector<int> uniqD;
    uniqD.reserve(byDelta.size());
    for (auto &p : byDelta)
        if (uniqD.empty() || uniqD.back() != p.first) uniqD.push_back(p.first);

    SegTree st(N - 1);

    auto imageContains = [&](const Node& F, int v) -> bool {
        int a = clampInt(F.S, F.L, F.R);
        int b = clampInt(VMAX + F.S, F.L, F.R);
        return a <= v && v <= b;
    };

    Node bestF = ident();
    int best_Tright = uniqD[0] - 1;
    if (!imageContains(bestF, V2)) {}

    int pos = 0;
    for (int g = 0; g < (int)uniqD.size(); ++g) {
        int dval = uniqD[g];
        while (pos < (int)byDelta.size() && byDelta[pos].first == dval) {
            int i = byDelta[pos].second;
            int leafIdx = i - 2;
            st.update(leafIdx, leafFromOp(op[i]));
            ++pos;
        }
        Node cur = st.all();
        if (imageContains(cur, V2)) {
            if (g == (int)uniqD.size() - 1) {
                cout << "infinity\n";
                return 0;
            }
            bestF = cur;
            best_Tright = uniqD[g + 1] - 1;
        }
    }

    int S = bestF.S, L = bestF.L, R = bestF.R;
    int V1;
    if (V2 == L) V1 = min(VMAX, L - S);
    else if (V2 == R) V1 = VMAX;
    else V1 = V2 - S;

    cout << best_Tright << ' ' << V1 << '\n';
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10