Submission #1261547

#	Time	Username	Problem	Language	Result	Execution time	Memory
1261547		hoa208	Examination (JOI19_examination)	C++20	100 / 100	370 ms	39808 KiB

examination

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

struct Point {
    int s;
    int t_idx;     // compressed index of T in allV (1-based)
    ll w;          // s + t
    int t_orig;    // original T (not strictly needed)
};

struct Query {
    int X;
    int Y;
    ll Z;
    int idx;       // original index
    int y_idx;     // compressed index of Y in allV (1-based)
};

struct FenwickSimple {
    // 1-indexed Fenwick for integers
    int n;
    vector<int> bit;
    FenwickSimple() {}
    FenwickSimple(int n_): n(n_), bit(n_+1, 0) {}
    void add(int i, int delta) {
        for (; i <= n; i += i & -i) bit[i] += delta;
    }
    int sumPrefix(int i) {
        int s = 0;
        for (; i > 0; i -= i & -i) s += bit[i];
        return s;
    }
};

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N, Q;
    if (!(cin >> N >> Q)) return 0;
    vector<pair<int,int>> pts(N);
    for (int i = 0; i < N; ++i) cin >> pts[i].first >> pts[i].second;
    vector<tuple<int,int,ll>> queries_input(Q);
    vector<Query> queries(Q);
    for (int j = 0; j < Q; ++j) {
        int X, Y;
        long long Z;
        cin >> X >> Y >> Z;
        queries_input[j] = {X, Y, Z};
        queries[j].X = X;
        queries[j].Y = Y;
        queries[j].Z = Z;
        queries[j].idx = j;
    }

    // 1) coordinate compress all T's and all Y's
    vector<int> allV;
    allV.reserve(N + Q);
    for (int i = 0; i < N; ++i) allV.push_back(pts[i].second);
    for (int j = 0; j < Q; ++j) allV.push_back(queries[j].Y);
    sort(allV.begin(), allV.end());
    allV.erase(unique(allV.begin(), allV.end()), allV.end());
    int M = (int)allV.size();

    // Build Points with compressed t_idx and w
    vector<Point> points(N);
    for (int i = 0; i < N; ++i) {
        int s = pts[i].first;
        int t = pts[i].second;
        int t_idx = int(lower_bound(allV.begin(), allV.end(), t) - allV.begin()) + 1; // 1-based
        points[i].s = s;
        points[i].t_idx = t_idx;
        points[i].w = (ll)s + (ll)t;
        points[i].t_orig = t;
    }
    // set y_idx for queries (first index with value >= Y)
    for (int j = 0; j < Q; ++j) {
        int Y = queries[j].Y;
        int y_idx = int(lower_bound(allV.begin(), allV.end(), Y) - allV.begin()) + 1; // 1-based
        // if Y is greater than all values, y_idx will be M+1. That's OK.
        queries[j].y_idx = y_idx;
    }

    // 2) Prepare bit nodes: for each point, push w into nodes i = t_idx .. M stepping by i&-i
    vector<vector<ll>> node_vals(M+1);
    for (int i = 0; i < N; ++i) {
        int idx = points[i].t_idx;
        ll w = points[i].w;
        for (int p = idx; p <= M; p += p & -p) node_vals[p].push_back(w);
    }
    // sort & unique each node's values and prepare FenwickSimple for each node
    vector<FenwickSimple> node_bit(M+1);
    vector<int> node_total(M+1, 0); // number of inserts done in that node
    for (int i = 1; i <= M; ++i) {
        auto &v = node_vals[i];
        if (!v.empty()) {
            sort(v.begin(), v.end());
            v.erase(unique(v.begin(), v.end()), v.end());
            node_bit[i] = FenwickSimple((int)v.size());
        }
    }

    // 3) Sort points by s descending and queries by X descending
    sort(points.begin(), points.end(), [](const Point &a, const Point &b){
        return a.s > b.s;
    });
    sort(queries.begin(), queries.end(), [](const Query &a, const Query &b){
        return a.X > b.X;
    });

    // helper functions: update a point (t_idx, w) into BIT-of-v
    auto update_point = [&](int t_idx, ll w) {
        for (int p = t_idx; p <= M; p += p & -p) {
            auto &vals = node_vals[p];
            if (vals.empty()) continue;
            int pos = int(lower_bound(vals.begin(), vals.end(), w) - vals.begin()); // 0-based
            // update FenwickSimple at pos+1 by +1
            node_bit[p].add(pos+1, 1);
            node_total[p] += 1;
        }
    };
    // query prefix up to idx (v <= idx), count w >= Z
    auto query_prefix = [&](int idx, ll Z) -> int {
        if (idx <= 0) return 0;
        if (idx > M) idx = M;
        int res = 0;
        for (int p = idx; p > 0; p -= p & -p) {
            auto &vals = node_vals[p];
            if (vals.empty()) continue;
            int pos = int(lower_bound(vals.begin(), vals.end(), Z) - vals.begin()); // number of values < Z
            int pref = node_bit[p].sumPrefix(pos); // count of w < Z
            // suffix = total - pref = count of w >= Z
            res += (node_total[p] - pref);
        }
        return res;
    };

    vector<int> ans(Q, 0);
    int cur_pt = 0; // index in points (sorted desc by s)
    for (int qi = 0; qi < Q; ++qi) {
        const Query &q = queries[qi];
        int X = q.X;
        // insert all points with s >= X
        while (cur_pt < N && points[cur_pt].s >= X) {
            update_point(points[cur_pt].t_idx, points[cur_pt].w);
            ++cur_pt;
        }
        int y_idx = q.y_idx;
        // if y_idx is M+1 (Y greater than any compressed value), then no v >= Y exists -> answer 0
        if (y_idx > M) {
            ans[q.idx] = 0;
            continue;
        }
        int total_up_to_M = query_prefix(M, q.Z);
        int up_to_before_y = query_prefix(y_idx - 1, q.Z);
        ans[q.idx] = total_up_to_M - up_to_before_y;
    }

    // print answers in original order
    for (int j = 0; j < Q; ++j) cout << ans[j] << '\n';
    return 0;
}

• Subtask 1: 2 / 2
• Subtask 2: 20 / 20
• Subtask 3: 21 / 21
• Subtask 4: 57 / 57