Submission #764231

#	Time	Username	Problem	Language	Result	Execution time	Memory
764231		Alma	Regions (IOI09_regions)	C++17	0 / 100	1694 ms	131072 KiB

regions

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

vector<int> region;
vector<bool> vis, calc;
vector<vector<int>> adj, dp, distrib;

void dfs(int u, int r) {
    vis[u] = true;

    if (region[u] != r) {
        dp[r][region[u]]++;
    } 
    for (int v: adj[u]) {
        if (!vis[v]) dfs(v, r);
    }
}

void dfs2(int u, int r, int cnt) {
    vis[u] = true;

    if (region[u] == r) {
        dp[r][region[u]] += cnt;
        cnt++;
    }
    for (int v: adj[u]) {
        if (!vis[v]) dfs2(v, r, cnt);
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int n, r, q, h, s, r1, r2;
    cin >> n >> r >> q;

    region = vector<int>(n);
    adj = vector<vector<int>>(n);
    distrib = vector<vector<int>>(n);

    cin >> h;
    h--;
    region[0] = h;
    distrib[h].push_back(0);

    for (int i = 1; i < n; i++) {
        cin >> s >> h;
        h--; s--;
        region[i] = h;
        distrib[h].push_back(i);
        adj[s].push_back(i);
    }

    calc = vector<bool> (r, false);
    dp = vector<vector<int>> (r, vector<int>(r, 0));

    while (q--) {
        cin >> r1 >> r2;
        r1--; r2--;
        
        if (not calc[r1]) {
            vis = vector<bool>(n, false);
            for (int i: distrib[r1]) {
                if (!vis[i]) dfs(i, r1);
            }
            vis = vector<bool>(n, false);
            dfs2(0, r1, 0);
            calc[r1] = true;
        }

        cout << dp[r1][r2] << endl << flush;
    }

    return 0;
}

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