Submission #798475

#	Time	Username	Problem	Language	Result	Execution time	Memory
798475		PurpleCrayon	Two Antennas (JOI19_antennas)	C++17	13 / 100	3068 ms	15824 KiB

antennas

#include <bits/stdc++.h>
using namespace std;
 
#define sz(v) int(v.size())
#define ar array
typedef long long ll;
const int N = 2e5+10, MOD = 1e9+7;

// activate i, deactivate i
// setmax range of active things
// query max{value - h[i]}
//
// support this with lazy segtree?

int n, q, h[N], a[N], b[N], ans[N];
ar<int, 2> qs[N];
vector<pair<int, int>> ql[N];

bool on[N];
int t[N];

void toggle(int x) {
    on[x] ^= 1;
}

void upd(int l, int r, int x) {
    for (int i = l; i <= r; i++) if (on[i])
        t[i] = max(t[i], x);
}

int qry(int l, int r) {
    int cur = -1;
    for (int i = l; i <= r; i++)
        cur = max(cur, t[i] - h[i]);
    return cur;
}

void calc() {
    for (int i = 0; i < n; i++) ql[i].clear();

    vector<vector<int>> ev(n);
    for (int i = 0; i < n; i++) {
        int L = i - b[i], R = i - a[i];
        L = max(L, 0);
        if (L <= R) {
            ev[R].push_back(i);
            if (L) ev[L-1].push_back(i);
        }
    }

    for (int i = 0; i < q; i++) {
        auto [l, r] = qs[i];
        ql[l].push_back({r, i});
    }

    memset(t, -1, sizeof(t));
    memset(on, 0, sizeof(on));
    for (int i = n-1; i >= 0; i--) {
        for (int x : ev[i]) toggle(x);
        int L = i + a[i], R = i + b[i];
        R = min(R, n-1);

        if (L <= R)
            upd(L, R, h[i]);

        for (auto [r, id] : ql[i]) {
            ans[id] = max(ans[id], qry(i, r));
        }
    }
}

void solve() {
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> h[i] >> a[i] >> b[i];
    }

    cin >> q;
    for (int i = 0; i < q; i++) {
        int l, r; cin >> l >> r, --l, --r;
        qs[i] = {l, r};
    }

    memset(ans, -1, sizeof(ans));
    for (int rep = 0; rep < 2; rep++) {
        calc();

        reverse(h, h + n);
        reverse(a, a + n);
        reverse(b, b + n);
        for (int i = 0; i < q; i++) {
            auto [l, r] = qs[i];
            qs[i] = {n - 1 - r, n - 1 - l};
        }
    }

    for (int i = 0; i < q; i++) {
        cout << ans[i] << '\n';
    }
}
 
int main() {
    ios::sync_with_stdio(false); cin.tie(0);
    int T = 1;
    // cin >> T;
    while (T--) solve();
}

• Subtask 1: 2 / 2
• Subtask 2: 11 / 11
• Subtask 3: 0 / 22
• Subtask 4: 0 / 65