Submission #110006

#	Time	Username	Problem	Language	Result	Execution time	Memory
110006		popovicirobert	Bulldozer (JOI17_bulldozer)	C++14	75 / 100	2056 ms	33492 KiB

bulldozer

#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long
// 217
// 44

using namespace std;

const ll INF = 1e18;

struct SegTree {

    struct Node {
        ll pref, suff;
        ll best, sum;
    };

    vector <Node> aint;
    int n;

    inline void init(int _n) {
        n = _n;
        aint.resize(4 * n + 1, {-INF, -INF, -INF, -INF});
    }

    inline void refresh(int nod) {
        aint[nod].sum = aint[2 * nod].sum + aint[2 * nod + 1].sum;
        aint[nod].pref = max(aint[2 * nod].pref, aint[2 * nod].sum + aint[2 * nod + 1].pref);
        aint[nod].suff = max(aint[2 * nod + 1].suff, aint[2 * nod + 1].sum + aint[2 * nod].suff);
        aint[nod].best = max(max(aint[2 * nod].best, aint[2 * nod + 1].best), aint[2 * nod].suff + aint[2 * nod + 1].pref);
    }

    void update(int nod, int left, int right, int pos, int val) {
        if(left == right) {
            aint[nod] = {val, val, val, val};
        }
        else {
            int mid = (left + right) / 2;
            if(pos <= mid) update(2 * nod, left, mid, pos, val);
            else update(2 * nod + 1, mid + 1, right, pos, val);
            refresh(nod);
        }
    }

};

struct Point {
    int x, y;
    int val;
    bool operator <(const Point &other) const {
        if(x == other.x)
            return y < other.y;
        return x < other.x;
    }
};

struct Slope {
    double s;
    int a, b;
    bool operator <(const Slope &other) const {
        return other.s - s > 0.0;
    }
};

inline double get(Point &a, Point &b) {
    if(a.x == b.x)
        return 1.0 * INF;
    return 1.0 * (b.y - a.y) / (b.x - a.x);
}

int main() {
    //ifstream cin("A.in");
    //ofstream cout("A.out");
    int i, j, n;
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    cin >> n;

    vector <Point> pts(n + 1);
    for(i = 1; i <= n; i++) {
        cin >> pts[i].x >> pts[i].y >> pts[i].val;
    }

    sort(next(pts.begin()), pts.end());

    vector <Slope> slp;
    for(i = 1; i <= n; i++) {
        for(j = i + 1; j <= n; j++) {
            slp.push_back({get(pts[i], pts[j]), i, j});
        }
    }

    sort(slp.begin(), slp.end());

    SegTree st; st.init(n);
    vector <int> pos(n + 1);

    for(i = 1; i <= n; i++) {
        st.update(1, 1, n, i, pts[i].val);
        pos[i] = i;
    }

    ll ans = max(0LL, st.aint[1].best);

    for(auto it : slp) {
        int a = it.a, b = it.b;

        if(abs(pos[a] - pos[b]) > 1) {
            while(1) {

            }
        }

        st.update(1, 1, n, pos[a], pts[b].val);
        st.update(1, 1, n, pos[b], pts[a].val);
        swap(pos[a], pos[b]);

        ans = max(ans, st.aint[1].best);

    }

    cout << ans;

    //cin.close();
    //cout.close();
    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 20 / 20
• Subtask 3: 35 / 35
• Subtask 4: 20 / 20
• Subtask 5: 0 / 20