Submission #548382

#	Time	Username	Problem	Language	Result	Execution time	Memory
548382		Jomnoi	Regions (IOI09_regions)	C++17	100 / 100	3726 ms	47804 KiB

regions

#include <bits/stdc++.h>
#define DEBUG 0
using namespace std;

const int MAX_N = 2e5 + 10;
const int MAX_R = 3e4 + 10;;
const int B = 500;

int timer;
int H[MAX_N];
int sz[MAX_N], st[MAX_N], pos[MAX_N];
vector <int> graph[MAX_N];
vector <int> region[MAX_R];
map <int, int> ans[MAX_R];
int pre[MAX_N];

int get_size(const int &u) {
    timer++;
    st[u] = timer;
    pos[timer] = u;
    sz[u] = 1;
    for(auto v : graph[u]) {
        sz[u] += get_size(v);
    }
    return sz[u];
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    int N, R, Q;
    cin >> N >> R >> Q;
    for(int i = 1; i <= N; i++) {
        int S;
        if(i != 1) {
            cin >> S;
            graph[S].push_back(i);
        }
        cin >> H[i];
    }

    get_size(1);

    for(int i = 1; i <= N; i++) {
        region[H[i]].push_back(st[i]);
    }
    for(int i = 1; i <= R; i++) {
        sort(region[i].begin(), region[i].end());
    }

    for(int i = 1; i <= R; i++) {
        if(region[i].size() < B) {
            continue;
        }

        fill(pre, pre + N + 1, 0);
        for(auto v : region[i]) {
            pre[v]++;
            pre[v + sz[pos[v]]]--;
        }
        for(int j = 1; j <= N; j++) {
            pre[j] += pre[j - 1];
            ans[H[pos[j]]][i] += pre[j];
        }
    }

    for(int i = 1; i <= Q; i++) {
        int r1, r2;
        cin >> r1 >> r2;
        if(region[r1].size() >= B) {
            cout << ans[r2][r1] << endl;
            continue;
        }

        int res = 0;
        for(auto v : region[r1]) {
            res += upper_bound(region[r2].begin(), region[r2].end(), v + sz[pos[v]] - 1) - lower_bound(region[r2].begin(), region[r2].end(), v);
        }
        cout << res << endl;
    }
    return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 85 / 85