Submission #259410

#	Time	Username	Problem	Language	Result	Execution time	Memory
259410		keko37	Two Antennas (JOI19_antennas)	C++14	35 / 100	200 ms	55928 KiB

antennas

#include<bits/stdc++.h>

using namespace std;

typedef long long llint;
typedef pair <llint, llint> pi;

const int MAXN = 200005;
const int MAXM = 2005;
const llint INF = 1000000000000000000LL;

int n, q, ofs = 1;
int h[MAXN], a[MAXN], b[MAXN];
int cost[MAXM][MAXM], dp[MAXM][MAXM], res[MAXM][MAXM];
vector <int> v[MAXN];
llint mx[MAXN * 4], mn[MAXN * 4];

void precompute () {
    memset(cost, -1, sizeof cost);
    memset(dp, -1, sizeof dp);
    memset(res, -1, sizeof res);
    for (int i = 1; i <= n; i++) {
        for (int j = i + 1; j <= n; j++) {
            if (a[i] <= j - i && j - i <= b[i] && a[j] <= j - i && j - i <= b[j]) {
                cost[i][j] = abs(h[i] - h[j]);
            }
            dp[i][j] = max(dp[i][j - 1], cost[i][j]);
        }
    }
    for (int rig = 1; rig <= n; rig++) {
        for (int lef = rig - 1; lef >= 1; lef--) {
            res[lef][rig] = max(res[lef + 1][rig], dp[lef][rig]);
        }
    }
}

void update (int pos, int val, bool flg) {
    //cout << "update " << pos << " " << val << " " << flg << endl;
    pos += ofs;
    if (flg == 1) {
        mn[pos] = mx[pos] = val;
    } else {
        mn[pos] = INF; mx[pos] = -INF;
    }
    pos /= 2;
    while (pos > 0) {
        mn[pos] = min(mn[pos * 2], mn[pos * 2 + 1]);
        mx[pos] = max(mx[pos * 2], mx[pos * 2 + 1]);
        pos /= 2;
    }
}

pi upit (int x, int from, int to, int lo, int hi) {
    if (from <= lo && hi <= to) return {mn[x], mx[x]};
    if (to < lo || hi < from) return {INF, -INF};
    pi lef = upit(2 * x, from, to, lo, (lo + hi) / 2);
    pi rig = upit(2 * x + 1, from, to, (lo + hi) / 2 + 1, hi);
    return {min(lef.first, rig.first), max(lef.second, rig.second)};
}

void sweep () {
    for (int i = 1; i <= n; i++) {
        int lo = i + a[i], hi = i + b[i];
        if (lo <= n) v[lo].push_back(i);
        if (hi + 1 <= n) v[hi + 1].push_back(-i);
    }
    llint sol = 0;
    for (int i = 1; i <= n; i++) {
        for (auto x : v[i]) {
            if (x > 0) {
                update(x, h[x], 1);
            } else {
                update(-x, 0, 0);
            }
        }
        int lo = i - b[i], hi = i - a[i];
        if (hi < 1) continue;
        lo = max(lo, 1);
        //cout << "bla " << lo << " " << hi << endl;

        pi res = upit(1, lo, hi, 0, ofs - 1);
        if (res.first <= h[i]) sol = max(sol, h[i] - res.first);
        if (h[i] <= res.second) sol = max(sol, res.second - h[i]);
    }
    cout << sol << endl;
}

int main () {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> h[i] >> a[i] >> b[i];
    }
    cin >> q;
    if (n <= 2000) {
        precompute();
        for (int i = 0; i < q; i++) {
            int lef, rig;
            cin >> lef >> rig;
            cout << res[lef][rig] << '\n';
        }
    } else if (q <= 1) {
        cin >> q >> q;
        while (ofs < n + 1) ofs *= 2;
        for (int i = 0; i < 2 * ofs; i++) {
            mn[i] = INF;
            mx[i] = -INF;
        }
        sweep();
    }
    return 0;
}

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