Submission #612444

#	Time	Username	Problem	Language	Result	Execution time	Memory
612444		Jomnoi	Triple Jump (JOI19_jumps)	C++17	100 / 100	1127 ms	91736 KiB

jumps

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

const int MAX_N = 5e5 + 5;
const int MAX_Q = 5e5 + 5;
const int INF = 1e9 + 7;

int A[MAX_N];
int L[MAX_Q], R[MAX_Q], ans[MAX_Q];
vector <int> queries[MAX_N], updates[MAX_N];

struct Node {
    int ans, maxL, maxR;

    Node() {}
    Node(int a, int ml, int mr) : ans(a), maxL(ml), maxR(mr) {}

    Node operator+(const Node &o) const {
        int ans_, maxL_, maxR_;
        ans_ = max({ans, o.ans, maxL + o.maxR});
        maxL_ = max(maxL, o.maxL);
        maxR_ = max(maxR, o.maxR);
        return Node(ans_, maxL_, maxR_);
    }
}tree[4 * MAX_N];

void build(int idx, int l, int r) {
    if(l == r) {
        return void(tree[idx] = Node(-INF, -INF, A[l]));
    }

    int mid = (l + r) / 2;
    build(idx * 2, l, mid);
    build(idx * 2 + 1, mid + 1, r);
    tree[idx] = tree[idx * 2] + tree[idx * 2 + 1];
}

void update(int idx, int l, int r, int q, int x) {
    if(l == r) {
        tree[idx].maxL = max(tree[idx].maxL, x);
        tree[idx].ans = max(tree[idx].ans, tree[idx].maxL + tree[idx].maxR);
        return;
    }

    int mid = (l + r) / 2;
    if(q <= mid) {
        update(idx * 2, l, mid, q, x);
    }
    else {
        update(idx * 2 + 1, mid + 1, r, q, x);
    }
    tree[idx] = tree[idx * 2] + tree[idx * 2 + 1];
}

Node query(int idx, int l, int r, int ql, int qr) {
    if(r < ql or qr < l) {
        return Node(-INF, -INF, -INF);
    }
    if(ql <= l and r <= qr) {
        return tree[idx];
    }

    int mid = (l + r) / 2;
    return query(idx * 2, l, mid, ql, qr) + query(idx * 2 + 1, mid + 1, r, ql, qr);
}

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);

    int N;
    cin >> N;
    for(int i = 1; i <= N; i++) {
        cin >> A[i];
    }

    int Q;
    cin >> Q;
    for(int i = 1; i <= Q; i++) {
        cin >> L[i] >> R[i];

        queries[L[i]].push_back(i);
    }

    stack <int> stk;
    for(int i = 1; i <= N; i++) {
        while(!stk.empty() and A[stk.top()] <= A[i]) {
            updates[stk.top()].push_back(i);
            stk.pop();
        }
        if(!stk.empty()) {
            updates[stk.top()].push_back(i);
        }

        stk.push(i);
    }

    build(1, 1, N);
    for(int i = N; i >= 1; i--) {
        for(auto j : updates[i]) {
            if(2 * j - i <= N) {
                update(1, 1, N, 2 * j - i, A[i] + A[j]);
            }
        }
        for(auto j : queries[i]) {
            ans[j] = query(1, 1, N, L[j], R[j]).ans;
        }
    }

    for(int i = 1; i <= Q; i++) {
        cout << ans[i] << '\n';
    }
    return 0;
}

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