Submission #1064681

#	Time	Username	Problem	Language	Result	Execution time	Memory
1064681		Sharky	Triple Jump (JOI19_jumps)	C++17	100 / 100	711 ms	90452 KiB

jumps

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

const int N = 5e5 + 8;
int n, q, a[N], ans[N], mx[N];
vector<int> pr[N];
vector<pair<int, int>> qry[N];
stack<pair<int, int>> stk;

struct Node {
    int pf, sf, sum;
} seg[4 * N];

Node merge(Node lhs, Node rhs) {
    Node res;
    res.pf = max(lhs.pf, rhs.pf);
    res.sf = max(lhs.sf, rhs.sf);
    res.sum = max({lhs.sum, rhs.sum, lhs.pf + rhs.sf});
    return res;
}

void build(int l, int r, int id) {
    if (l == r) {
        seg[id].pf = 0;
        seg[id].sf = seg[id].sum = a[l];
        return;
    }
    int mid = (l + r) >> 1;
    build(l, mid, id * 2);
    build(mid + 1, r, id * 2 + 1);
    seg[id] = merge(seg[id * 2], seg[id * 2 + 1]);
}

void update(int pos, int val, int l, int r, int id) {
    if (l == r) {
        seg[id].pf = val;
        seg[id].sum = seg[id].pf + seg[id].sf;
        return;
    }
    int mid = (l + r) >> 1;
    if (pos <= mid) update(pos, val, l, mid, id * 2);
    else update(pos, val, mid + 1, r, id * 2 + 1);
    seg[id] = merge(seg[id * 2], seg[id * 2 + 1]);
}

Node query(int ql, int qr, int l, int r, int id) {
    if (qr < l || r < ql) return {0, 0};
    if (ql <= l && r <= qr) return seg[id];
    int mid = (l + r) >> 1;
    return merge(query(ql, qr, l, mid, id * 2), query(ql, qr, mid + 1, r, id * 2 + 1));
}

int32_t main() {
    ios::sync_with_stdio(0); cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        while (!stk.empty() && stk.top().first <= a[i]) {
            pr[stk.top().second].push_back(i);
            stk.pop();
        }
        if (!stk.empty()) pr[stk.top().second].push_back(i);
        stk.push({a[i], i});
    }
    cin >> q;
    for (int i = 1; i <= q; i++) {
        int l, r;
        cin >> l >> r;
        qry[l].push_back({r, i});
    }
    build(1, n, 1);
    for (int i = n; i >= 1; i--) {
        for (int& j : pr[i]) {
            if (2 * j - i > n) continue;
            int nw = a[i] + a[j];
            if (nw > mx[2 * j - i]) {
                update(2 * j - i, nw, 1, n, 1);
                mx[2 * j - i] = nw;
                // cout << "upd: " << 2 * j - i << " " << nw << "\n";
            }
        }
        for (auto& [j, idx] : qry[i]) {
            // cout << "idx = " << idx << '\n';
            ans[idx] = query(i, j, 1, n, 1).sum;
        }
    }
    for (int i = 1; i <= q; i++) cout << ans[i] << '\n';
}

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