Submission #1202038

#	Time	Username	Problem	Language	Result	Execution time	Memory
1202038		onbert	Split the Attractions (IOI19_split)	C++20	18 / 100	66 ms	29884 KiB

split

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

const int maxn = 1e5 + 5;
int n, m;
vector<int> adj[maxn];
vector<int> adj1[maxn];

bool vis[maxn];
int fa[maxn], sz[maxn];
void dfs(int u) {
    sz[u] = vis[u] = 1;
    for (int v:adj[u]) if (!vis[v]) {
        fa[v] = u;
        adj1[u].push_back(v); adj1[v].push_back(u);
        dfs(v);
        sz[u] += sz[v];
    }
}

vector<int> ord;
void dfs1(int u, int p) {
    ord.push_back(u);
    for (int v:adj1[u]) if (v != p) dfs1(v, u);
}

vector<int> ans;
int root = -1;
int dsu[maxn], nodes[maxn];
int rt(int u) {
    if (dsu[u] == u) return u;
    return dsu[u] = rt(dsu[u]);
}
void merge(int u, int v) {
    u = rt(u), v = rt(v);
    if (u != v) {
        nodes[v] += nodes[u];
        dsu[u] = v;
    }
}

int anc[maxn];
void dfs2(int u, int p) {
    for (int v:adj1[u]) if (v != p) {
        anc[v] = anc[u];
        dfs2(v, u);
    }
}

vector<int> adj2[maxn];
void dfs3(int u, int p) {
    ord.push_back(u);
    for (int v:adj2[u]) if (v != p) dfs3(v, u);
}

void dfs4(int u) {
    ord.push_back(u);
    vis[u] = 1;
    for (int v:adj[u]) if (!vis[v] && !ans[v]) dfs4(v);
}

int test;
set<int> S;
void dfs5(int u) {
    test++, vis[u] = 1;
    S.insert(u);
    for (int v:adj[u]) if (!vis[v]) dfs5(v);
}

vector<int> find_split(int N, int a, int b, int c, vector<int> p, vector<int> q) {
    n = N, m = p.size();

    vector<pair<int,int>> vec = {{a, 1}, {b, 2}, {c, 3}};
    sort(vec.begin(), vec.end());
    for (int i=0;i<m;i++) {adj[p[i]].push_back(q[i]); adj[q[i]].push_back(p[i]);}
    fa[0] = -1;
    dfs(0);

    a = vec[0].first, b = vec[1].first;
    ans.resize(n);
    for (int i=0;i<n;i++) ans[i] = 0;

    for (int i=0;i<n;i++) {
        if (a <= sz[i] && sz[i] <= n-a) {
            if (sz[i] <= n-b) {
                for (int j=0;j<n;j++) ans[j] = vec[2].second;
                ord.clear();
                dfs1(i, fa[i]);
                for (int j=0;j<a;j++) ans[ord[j]] = vec[0].second;
                ord.clear();
                dfs1(fa[i], i);
                for (int j=0;j<b;j++) ans[ord[j]] = vec[1].second;
            } else {
                for (int j=0;j<n;j++) ans[j] = vec[2].second;
                ord.clear();
                dfs1(i, fa[i]);
                for (int j=0;j<b;j++) ans[ord[j]] = vec[1].second;
                ord.clear();
                dfs1(fa[i], i);
                for (int j=0;j<a;j++) ans[ord[j]] = vec[0].second;
            }
            return ans;
        }
    }

    for (int i=0;i<n;i++) if (n - sz[i] < a) {
        bool flag = true;
        for (int v:adj[i]) if (sz[v] >= a) flag = false;
        if (flag) root = i;
    }
    assert(root != -1);

    for (int i=0;i<n;i++) vis[i] = 0;
    vis[root] = 1;
    int cnt = 0;
    for (int i=0;i<n;i++) if (!vis[i]) {
        test = 0;
        dfs5(i);
        cnt++;
    }
    // assert(cnt == adj[root].size());

    return ans;

    // for (int v:adj1[root]) {
    //     anc[v] = v;
    //     dfs2(v, root);
    //     nodes[v] = sz[v];
    // }

    // for (int i=0;i<n;i++) dsu[i] = i;

    // for (int i=0;i<m;i++) if (p[i] != root && q[i] != root) {
    //     int u = anc[p[i]], v = anc[q[i]];
    //     int U = rt(u), V = rt(v);
    //     if (U == V) continue;
    //     merge(U, V);
    //     adj2[U].push_back(V); adj2[V].push_back(U);
    //     if (nodes[V] >= a) {
    //         ord.clear();
    //         dfs3(V, -1);
    //         int cnt = 0;
    //         for (int j:ord) {
    //             ans[j] = vec[0].second;
    //             cnt += sz[j];
    //             if (cnt >= a) break;
    //         }
    //         for (int j=0;j<n;j++) if (j != root && ans[anc[j]]) {
    //             ans[j] = vec[0].second;
    //         }

    //         ord.clear();
    //         for (int j=0;j<n;j++) vis[j] = 0;
    //         dfs4(root);
    //         for (int j=0;j<b;j++) ans[ord[j]] = vec[1].second;

    //         for (int j=0;j<n;j++) if (!ans[j]) ans[j] = vec[2].second;
    //         return ans;
    //     }
    // }

}

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 0 / 22
• Subtask 4: 0 / 24
• Subtask 5: 0 / 36