Submission #841404

#	Time	Username	Problem	Language	Result	Execution time	Memory
841404		model_code	Beech Tree (IOI23_beechtree)	C++17	31 / 100	420 ms	109216 KiB

beechtree

// correct/sol_db_twoColors.cpp

#include "beechtree.h"
#include <bits/stdc++.h>

#define all(x) (x).begin(), (x).end()
#define xx first
#define yy second

using namespace std;
typedef pair<int, int> pii;
const int N = 2e5 + 1;

struct Graph
{
    int cnt[N];
    bool con[N];
    set<pii> srt[N];
    vector<int> adj[N][2];
} graph;

bool check(int v, int u)
{
    for (int c = 0; c < 2; ++c)
    {
        if (graph.adj[v][c].empty())
        {
            continue;
        }
        if (graph.adj[u][c].empty())
        {
            return false;
        }
        if (graph.cnt[graph.adj[v][c][0]] > graph.cnt[graph.adj[u][c][0]])
        {
            return false;
        }
    }
    return true;
}

bool insertAndCheck(set<pii> &srt, pii p)
{
    auto [it, st] = srt.insert(p);
    bool result = true;
    if (it != srt.begin())
    {
        result &= check(prev(it)->yy, it->yy);
    }
    if (next(it) != srt.end())
    {
        result &= check(it->yy, next(it)->yy);
    }
    return result;
}

int dfs(int u)
{
    graph.cnt[u] = 1;
    graph.con[u] = true;

    for (int c = 0; c < 2; ++c)
    {
        auto &vec = graph.adj[u][c];
        graph.con[u] &= vec.size() <= 1;

        for (int v : vec)
        {
            int cnv = dfs(v);
            if (cnv == -1)
            {
                graph.con[u] = false;
            }
            else
            {
                graph.cnt[u] += cnv;
            }
            if (graph.con[u])
            {
                if (graph.srt[v].size() > graph.srt[u].size())
                {
                    graph.srt[u].swap(graph.srt[v]);
                }
                for (pii p : graph.srt[v])
                {
                    graph.con[u] &= insertAndCheck(graph.srt[u], p);
                }
            }
        }
    }
    graph.con[u] &= insertAndCheck(graph.srt[u], {graph.cnt[u], u});
    return graph.con[u] ? graph.cnt[u] : -1;
}

vector<int> beechtree(int n, int m, vector<int> P, vector<int> C)
{
    for (int i = 1; i < n; ++i)
    {
        int p = P[i];
        int c = C[i];
        graph.adj[p][c - 1].push_back(i);
    }
    dfs(0);

    vector<int> ans;
    for (int i = 0; i < n; ++i)
        ans.push_back(graph.con[i]);
    return ans;
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 9
• Subtask 2: 0 / 5
• Subtask 3: 0 / 9
• Subtask 4: 0 / 8
• Subtask 5: 0 / 14
• Subtask 6: 14 / 14
• Subtask 7: 0 / 12
• Subtask 8: 17 / 17
• Subtask 9: 0 / 12