Submission #1213891

#	Time	Username	Problem	Language	Result	Execution time	Memory
1213891		vanea	Regions (IOI09_regions)	C++20	0 / 100	483 ms	30040 KiB

regions

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

const int mxN = 2e5+10;
const int mxR = 3e4+10;

int reg[mxN], bit[mxN];
vector<int> adj[mxN], emp[mxR];
int tin[mxN], tout[mxN], timer = 0;
int ans1[510][510], cnt[mxN];

void dfs(int node, int p) {
    tin[node] = ++timer;
    for(auto it : adj[node]) {
        if(it == p) continue;
        dfs(it, node);
    }
    tout[node] = timer;
}

void upd(int k, int x) {
    for(k; k < mxN; k += ((k) & (-k))) {
        bit[k] += x;
    }
}

int qry(int k) {
    int ans = 0;
    for(; k >= 1; k -= ((k) & (-k))) {
        ans += bit[k];
    }
    return ans;
}

void dfs1(int node, int p, int k) {
    cnt[node] = (reg[node] == k);
    for(auto it : adj[node]) {
        if(it == p) continue;
        dfs1(it, node, k);
        cnt[node] += cnt[it];
    }
    ans1[reg[node]][k] += cnt[node];
}

int main()
{
    int n, r, q;
    cin >> n >> r >> q;
    cin >> reg[1];
    emp[reg[1]].push_back(1);
    for(int i = 2; i <= n; i++) {
        int p;
        cin >> p >> reg[i];
        emp[reg[i]].push_back(i);
        adj[p].push_back(i);
        adj[i].push_back(p);
    }
    dfs(1, 0);
    if(r <= 500) {
        for(int r1 = 1; r1 <= r; r1++) {
            dfs1(1, 0, r1);
        }
    }
    int mx = 0;
    vector<int> answers(q+1);
    vector<array<int, 2>> queries;
    vector<vector<array<int, 2>>> qrs(q+1);
    for(int i = 0; i < q; i++) {
        int r1, r2;
        cin >> r1 >> r2;
        queries.push_back({r1, r2});
        qrs[r2].push_back({r1, i});
    }
    for(int r2 = r; r2 >= 1; r2--) {
        if(qrs[r2].empty()) continue;
        for(auto it : emp[r2]) {
            upd(tin[it], 1);
        }
        for(auto [r1, idx] : qrs[r2]) {
            int ans = 0;
            for(auto it : emp[r1]) {
                ans += qry(tout[it]) - qry(tin[it]-1);
            }
            answers[idx] = ans;
        }
        for(auto it : emp[r2]) {
            upd(tin[it], -1);
        }
    }
    for(int i = 0; i < q; i++) {
        int r1 = queries[i][0], r2 = queries[i][1];
        if(r <= 500) {
            cout << ans1[r1][r2] << '\n';
            cout.flush();
            continue;
        }/*
        else if(emp[r1].size() <= 500 && emp[r2].size() <= 500) {
            int ans = 0;
            for(auto it : emp[r2]) {
                upd(tin[it], 1);
            }
            for(auto it : emp[r1]) {
                ans += qry(tout[it])-qry(tin[it]-1);
            }
            for(auto it : emp[r2]) {
                upd(tin[it], -1);
            }
            cout << ans << '\n';
            cout.flush();
        }*/
        else {
            cout << answers[i] << '\n';
            cout.flush();
        }
    }
    return 0;
}

• Subtask 1: 0 / 15
• Subtask 2: 0 / 85