Submission #1213529

#	Time	Username	Problem	Language	Result	Execution time	Memory
1213529		vanea	Regions (IOI09_regions)	C++20	70 / 100	8093 ms	25428 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);
        }
    }
    while(q--) {
        int r1, r2;
        cin >> r1 >> r2;
        if(r <= 500) {
            cout << ans1[r1][r2] << '\n';
            cout.flush();
            continue;
        }
        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();
    }
    return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 55 / 85