Submission #492060

#	Time	Username	Problem	Language	Result	Execution time	Memory
492060		davi_bart	Friend (IOI14_friend)	C++14	16 / 100	14 ms	20340 KiB

friend

#include "friend.h"
#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
// #define int ll
#define fi first
#define se second
#define ld long double
#define pb push_back
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
set<int> v[100010];
vector<bool> vis(100010, 0);
set<int> figli[100010];
vector<int> p(100010);
void dfs(int pos, int par) {
    if (vis[pos]) return;
    vis[pos] = 1;
    if (par != -1) figli[par].insert(pos);
    p[pos] = par;
    for (int x : v[pos]) dfs(x, pos);
}
int memo[100010][2];
vector<int> conf;

int findSample(int N, int confidence[], int host[], int protocol[]) {
    for (int i = 0; i < N; i++) conf.pb(confidence[i]);
    int a[3] = {0, 0, 0};
    for (int i = 1; i < N; i++) {
        a[protocol[i]]++;
    }
    if (a[1] == N - 1) {
        int tot = 0;
        for (int i = 0; i < N; i++) tot += confidence[i];
        return tot;
    }
    if (a[2] == N - 1) {
        int tot = 0;
        for (int i = 0; i < N; i++) tot = max(confidence[i], tot);
        return tot;
    }

    for (int i = 1; i < N; i++) {
        if (protocol[i] == 1 || protocol[i] == 2) {
            for (int x : v[host[i]]) {
                v[x].insert(i);
                v[i].insert(x);
            }
        }
        if (protocol[i] == 0 || protocol[i] == 2) {
            v[host[i]].insert(i);
            v[i].insert(host[i]);
        }
    }
    int ans = 0;

    for (int i = 0; i < N; i++) {
        if (!vis[i]) {
            dfs(i, -1);
        }
    }

    int tolti = 0;
    bool ok = 1;
    vector<bool> elim(N, 0);
    while (ok) {
        vector<int> k;
        ok = 0;
        // cout << "ok" << endl;
        for (int i = 0; i < N; i++) {
            if (v[i].size() <= 1 && !elim[i]) {
                ans++;
                k.pb(i);
                ok = 1;
                elim[i] = 1;
            }
        }
        for (int x : k) {
            if (v[x].size() > 0) {
                int u = *v[x].begin();
                // cout << x << endl;
                elim[u] = 1;
                for (int y : v[u]) {
                    v[y].erase(u);
                    v[u].erase(y);
                }
                tolti++;
            }
        }
    }
    // cout << ans << " " << tolti << endl;
    return ans + (N - ans - tolti) / 2;
}

• Subtask 1: 0 / 11
• Subtask 2: 8 / 8
• Subtask 3: 8 / 8
• Subtask 4: 0 / 19
• Subtask 5: 0 / 23
• Subtask 6: 0 / 31