Submission #1214096

#	Time	Username	Problem	Language	Result	Execution time	Memory
1214096		iamhereforfun	Regions (IOI09_regions)	C++20	100 / 100	2429 ms	29100 KiB

regions

// IamHereForFun //

#include <bits/stdc++.h>

using namespace std;

#define LSOne(X) ((X) & -(X))

const int N = 2e5 + 5;
const int M = 1e2 + 5;
const int C = 26;
const int LG = 20;
const int R = 25e3 + 5;
const int B = 450;
const int INF = 1e9 + 5;
const int MOD = 1e9 + 7;

int n, r, q, home[N], cnt_home[N], heavy[B][R], in[N], out[N], cid = 0, heavy_idx[R];
vector<pair<int, int>> range[R];
vector<int> adj[N];

void dfs1(int c)
{
    in[c] = cid++;
    for(int i : adj[c])
    {
        dfs1(i);
    }
    out[c] = cid++;
    // cout << home[c] << "\n";
    range[home[c]].push_back({in[c], out[c]});
}

void dfs2(int c, int t, int cnt)
{
    if(home[c] == t) cnt++;
    heavy[heavy_idx[t]][home[c]] += cnt;
    for(int i : adj[c])
    {
        dfs2(i, t, cnt);
    }
}

void solve()
{
    cin >> n >> r >> q;
    cin >> home[1];
    cnt_home[home[1]]++;
    for(int x = 2; x <= n; x++)
    {
        int i; cin >> i;
        adj[i].push_back(x);
        cin >> home[x];
        cnt_home[home[x]]++;
    }
    dfs1(1);
    cid = 0;
    for(int x = 1; x <= r; x++)
    {
        if(cnt_home[x] >= B)
        {
            heavy_idx[x] = cid++;
            dfs2(1, x, 0);
        }
    }
    for(int x = 1; x <= r; x++) sort(range[x].begin(), range[x].end());
    for(int x = 0; x < q; x++)
    {
        int r1, r2; cin >> r1 >> r2;
        if(cnt_home[r1] >= B)
        {
            cout << heavy[heavy_idx[r1]][r2] << endl;
        }
        else
        {
            int ans = 0;
            for(pair<int, int> p : range[r1])
            {
                ans += lower_bound(range[r2].begin(), range[r2].end(), make_pair(p.second, 0)) - lower_bound(range[r2].begin(), range[r2].end(), make_pair(p.first, 0));
            }
            cout << ans << endl;
        }
    }
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    // cin >> t;
    for (int x = 1; x <= t; x++)
    {
        solve();
    }
    return 0;
}

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