Submission #1145486

#	Time	Username	Problem	Language	Result	Execution time	Memory
1145486		VMaksimoski008	Triple Jump (JOI19_jumps)	C++20	100 / 100	891 ms	115520 KiB

jumps

#include <bits/stdc++.h>
#define ar array
//#define int long long

using namespace std;

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

const int mod = 1e9 + 7;
const ll inf = 1e18;
const int maxn = 1e5 + 5;

struct segment_tree {
    struct node {
        ll pref, suf, ans;
        node(ll a=-5e9, ll b=-5e9) { pref = a; suf = b; ans = a + b; }
    };

    node merge(node a, node b) {
        node res;
        res.pref = max(a.pref, b.pref);
        res.suf = max(a.suf, b.suf);
        res.ans = max({ a.ans, b.ans, a.pref + b.suf });
        return res;
    }

    int n;
    vector<node> tree;

    segment_tree(int _n): n(_n), tree(4*n) {}

    void update(int u, int tl, int tr, int p, int t, int v) {
        // cout << p << " !\n";
        if(tl == tr) {
            if(!t) tree[u].pref = max(tree[u].pref, (ll)v);
            else tree[u].suf = max(tree[u].suf, (ll)v);
            tree[u].ans = max(tree[u].pref + tree[u].suf, tree[u].ans);
        } else {    
            int tm = (tl + tr) / 2;
            if(p <= tm) update(2*u, tl, tm, p, t, v);
            else update(2*u+1, tm+1, tr, p, t, v);
            tree[u] = merge(tree[2*u], tree[2*u+1]);
        }
    }

    node query(int u, int tl, int tr, int l, int r) {
        if(tl > r || l > tr) return node();
        if(l <= tl && tr <= r) return tree[u];
        int tm = (tl + tr) / 2;
        return merge(query(2*u, tl, tm, l, r), query(2*u+1, tm+1, tr, l, r));
    }

    void update(int p, int t, int v) { update(1, 1, n, p, t, v); }
    node query(int l, int r) { return query(1, 1, n, l, r); }
};

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

    int n, q; cin >> n;
    vector<int> a(n+1);
    for(int i=1; i<=n; i++) cin >> a[i];
    vector<int> add[n+1];

    stack<int> st;
    for(int i=n; i>=1; i--) {
        while(!st.empty() && a[st.top()] < a[i]) st.pop();
        if(!st.empty()) add[i].push_back(st.top());
        st.push(i);
    }

    while(!st.empty()) st.pop();
    for(int i=n; i>=1; i--) {
        while(!st.empty() && a[st.top()] >= a[i]) st.pop();
        if(!st.empty()) add[i].push_back(st.top());
        st.push(i);
    }

    while(!st.empty()) st.pop();
    for(int i=1; i<=n; i++) {
        while(!st.empty() && a[st.top()] < a[i]) st.pop();
        if(!st.empty()) add[st.top()].push_back(i);
        st.push(i);
    }

    while(!st.empty()) st.pop();
    for(int i=1; i<=n; i++) {
        while(!st.empty() && a[st.top()] >= a[i]) st.pop();
        if(!st.empty()) add[st.top()].push_back(i);
        st.push(i);
    }

    cin >> q;
    vector<ar<int, 2> > qus[n+1];

    for(int i=1; i<=q; i++) {
        int l, r; cin >> l >> r;
        qus[l].push_back({ r, i });
    }

    vector<ll> ans(q+1);

    segment_tree sgt(n);
    for(int i=n; i>=1; i--) {
        for(int j : add[i])
            if(2*j-i <= n) sgt.update(2*j-i, 0, a[i] + a[j]);
        sgt.update(i, 1, a[i]);
        for(auto [j, id] : qus[i]) ans[id] = sgt.query(i, j).ans;
    }

    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