Submission #617403

#	Time	Username	Problem	Language	Result	Execution time	Memory
617403		happypotato	Keys (IOI21_keys)	C++17	37 / 100	162 ms	37112 KiB

keys

#include <vector>
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define pii pair<int, int>
#define ff first
#define ss second
const int mxN = 3e5 + 1;
vector<pii> edges[mxN];
vector<int> adj[mxN];
bool vis[mxN], key[mxN];
int val[mxN];
int dsu[mxN];
vector<int> nodes[mxN];
int n, m;
void reset() {
    for (int i = 1; i <= n; i++) {
        // adj[i].clear();
        vis[i] = false;
        key[i] = false;
        dsu[i] = -1;
        nodes[i] = {i};
    }
}
int tar;
int DSUFind(int u) {
    if (dsu[u] == -1) return u;
    return (dsu[u] = DSUFind(dsu[u]));
}
int DSUUnion(int u, int v) {
    u = DSUFind(u);
    v = DSUFind(v);
    if (nodes[u].size() < nodes[v].size()) swap(u, v);
    if (u != tar && v == tar) swap(u, v);
    if (u != v) {
        dsu[v] = u;
        if (u == tar) return v;
        for (int &x : nodes[v]) nodes[u].pb(x);
    }
    return 0;
}
int simulate(int u) {
    tar = u;
    int ans = 1;
    queue<int> process;
    process.push(u);
    while (!process.empty()) {
        int cur = process.front();
        process.pop();
        if (!key[val[cur]]) {
            for (pii edge : edges[val[cur]]) {
                int ret = DSUUnion(edge.ff, edge.ss);
                if (!ret) continue;
                ans += nodes[ret].size();
                for (int &x : nodes[ret]) process.push(x);
            }
            key[val[cur]] = true;
        }
    }
    return ans;
}
vector<int> find_reachable(vector<int> r, vector<int> u, vector<int> v, vector<int> c) {
    n = r.size();
    m = c.size();
    for (int i = 0; i < n; i++) {
        r[i]++;
    }
    for (int i = 0; i < m; i++) {
        u[i]++;
        v[i]++;
        c[i]++;
    }
    for (int i = 1; i <= n; i++) {
        val[i] = r[i - 1];
    }
    for (int i = 0; i < m; i++) {
        edges[c[i]].pb({u[i], v[i]});
    }
    if (n <= 2000 && m <= 2000) {
        int dist[n + 1];
        int mini = n + 1;
        for (int i = 1; i <= n; i++) {
            reset();
            dist[i] = simulate(i);
            mini = min(mini, dist[i]);
        }
        vector<int> ans;
        for (int i = 1; i <= n; i++) {
            ans.pb(dist[i] == mini);
        }
        return ans;
    }
    return {};
}

• Subtask 1: 9 / 9
• Subtask 2: 11 / 11
• Subtask 3: 17 / 17
• Subtask 4: 0 / 30
• Subtask 5: 0 / 33