Submission #168567

#	Time	Username	Problem	Language	Result	Execution time	Memory
168567		popovicirobert	Triple Jump (JOI19_jumps)	C++14	100 / 100	1436 ms	59652 KiB

jumps

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



#if 1
const int MOD = (int) 998244353;

inline int lgput(int a, int b) {
    int ans = 1;
    while(b > 0) {
        if(b & 1) ans = (1LL * ans * a) % MOD;
        b >>= 1;
        a = (1LL * a * a) % MOD;
    }
    return ans;
}

inline void mod(int &x) {
    if(x >= MOD)
        x -= MOD;
}

inline void add(int &x, int y) {
    x += y;
    mod(x);
}

inline void sub(int &x, int y) {
    x += MOD - y;
    mod(x);
}

inline void mul(int &x, int y) {
    x = (1LL * x * y) % MOD;
}

inline int inv(int x) {
    return lgput(x, MOD - 2);
}
#endif

#if 0
int fact[], invfact[];

inline void prec(int n) {
    fact[0] = 1;
    for(int i = 1; i <= n; i++) {
        fact[i] = (1LL * fact[i - 1] * i) % MOD;
    }
    invfact[n] = lgput(fact[n], MOD - 2);
    for(int i = n - 1; i >= 0; i--) {
        invfact[i] = (1LL * invfact[i + 1] * (i + 1)) % MOD;
    }
}

inline int comb(int n, int k) {
    if(n < k) return 0;
    return (1LL * fact[n] * (1LL * invfact[k] * invfact[n - k] % MOD)) % MOD;
}
#endif

using namespace std;

const int INF = 1e9;

struct Node {
    int best;
    int mx, lazy;
    Node() {
        best = mx = lazy = -INF;
    }
};

struct SegTree {

    vector <Node> aint;
    int n;

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

    inline Node combine(Node a, Node b) {
        Node ans;
        ans.best = max(max(a.best, b.best), max(a.mx + a.lazy, b.mx + b.lazy));
        ans.mx = max(a.mx, b.mx);
        return ans;
    }

    inline void push(int nod) {
        if(2 * nod + 1 <= 4 * n) {
            aint[2 * nod].lazy = max(aint[2 * nod].lazy, aint[nod].lazy);
            aint[2 * nod + 1].lazy = max(aint[2 * nod + 1].lazy, aint[nod].lazy);
        }
        aint[nod].best = max(aint[nod].best, aint[nod].mx + aint[nod].lazy);
        aint[nod].lazy = -INF;
    }

    void build(int nod, int left, int right, vector <int> &a) {
        if(left == right) {
            aint[nod].mx = a[left];
        }
        else {
            int mid = (left + right) / 2;

            build(2 * nod, left, mid, a);
            build(2 * nod + 1, mid + 1, right, a);

            aint[nod] = combine(aint[2 * nod], aint[2 * nod + 1]);
        }
    }

    void update(int nod, int left, int right, int l, int r, int val) {
        push(nod);

        if(left > r || right < l) return ;

        if(l <= left && right <= r) {
            aint[nod].lazy = max(aint[nod].lazy, val);
            push(nod);
            return ;
        }

        int mid = (left + right) / 2;

        update(2 * nod, left, mid, l, r, val);
        update(2 * nod + 1, mid + 1, right, l, r, val);

        aint[nod] = combine(aint[2 * nod], aint[2 * nod + 1]);
    }

    int query(int nod, int left, int right, int l, int r) {
        push(nod);

        if(left > r || right < l) return -INF;

        if(l <= left && right <= r) {
            return aint[nod].best;
        }

        int mid = (left + right) / 2;
        int ans = max(query(2 * nod, left, mid, l, r), query(2 * nod + 1, mid + 1, right, l, r));

        aint[nod] = combine(aint[2 * nod], aint[2 * nod + 1]);

        return ans;
    }
};

int main() {
#ifdef HOME
    ifstream cin("A.in");
    ofstream cout("A.out");
#endif
    int i, n, q;
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    cin >> n;

    vector <int> a(n + 1);
    for(i = 1; i <= n; i++) {
        cin >> a[i];
    }

    stack <int> stk;
    vector <int> nxt(n + 1);

    for(i = 1; i <= n; i++) {
        while(stk.size() && a[stk.top()] < a[i]) {
            nxt[stk.top()] = i;
            stk.pop();
        }
        stk.push(i);
    }

    while(stk.size()) {
        nxt[stk.top()] = n + 1;
        stk.pop();
    }

    struct Segm {
        int l, r;
        bool operator <(const Segm &other) const {
            return l > other.l;
        }
    };

    vector <Segm> segm;

    for(i = 1; i <= n; i++) {
        int p = i + 1, mx = 0;
        while(p <= n && a[i] > mx) {
            segm.push_back({i, p});
            mx = max(mx, a[p]);
            p = nxt[p];
        }
    }

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

    cin >> q;

    struct Query {
        int l, r, pos;
        bool operator <(const Query &other) const {
            return l > other.l;
        }
    };

    vector <Query> qry(q);
    for(i = 0; i < q; i++) {
        cin >> qry[i].l >> qry[i].r;
        qry[i].pos = i + 1;
    }

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

    vector <int> sol(q + 1);
    int pos = 0, sz = segm.size();

    SegTree st; st.init(n);
    st.build(1, 1, n, a);

    for(i = 0; i < q; i++) {
        while(pos < sz && segm[pos].l >= qry[i].l) {
            if(2 * segm[pos].r - segm[pos].l <= n) {
                st.update(1, 1, n, 2 * segm[pos].r - segm[pos].l, n, a[segm[pos].l] + a[segm[pos].r]);
            }
            pos++;
        }
        sol[qry[i].pos] = st.query(1, 1, n, qry[i].l + 2, qry[i].r);
    }


    for(i = 1; i <= q; i++) {
        cout << sol[i] << "\n";
    }

    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 14 / 14
• Subtask 3: 27 / 27
• Subtask 4: 54 / 54