Submission #395608

#	Time	Username	Problem	Language	Result	Execution time	Memory
395608		idk321	Toy Train (IOI17_train)	C++11	5 / 100	83 ms	2556 KiB

train

#include "train.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int N = 5000;
set<int> adj[N];

vector<int> a;
vector<int> r;
vector<int> u;
vector<int> v;



bool miss[N];

int in[N];
int up[N];
int timer = 0;

bool goodA[N];
bool goodB[N];

vector<int> comps;

vector<int> st;
bool onSt[N];

void dfs(int node)
{
    timer++;
    in[node] = timer;
    up[node] = in[node];
    st.push_back(node);
    onSt[node] = true;
    for (int next : adj[node])
    {
        if (miss[next]) continue;
        if (next == node && r[node])
        {
            goodA[node] = true;
        }
        if (next == node) goodB[node] = true;

        if (in[next] == 0)
        {
            dfs(next);
            up[node] = min(up[node], up[next]);
        } else if (onSt[next])
        {
            up[node] = min(up[node], in[next]);
        }
    }

    if (in[node] == up[node])
    {
        vector<int> comp;
        bool aGood = false;
        bool bGood = false;
        while (st.back() != node)
        {
            onSt[st.back()] = false;
            if (r[st.back()]) aGood = true;
            bGood = true;
            comp.push_back(st.back());
            st.pop_back();
        }
        comp.push_back(node);
        st.pop_back();
        onSt[node] = false;
        if (comp.size() > 1 && r[node])
        {
            aGood = true;
        }
        if (comp.size() > 1) bGood = true;

        if (aGood)
        {
            for (int i : comp) goodA[i] = true;
        }
        if (bGood) for (int i : comp) goodB[i] = true;
    }
}

bool vis[N];

bool reachGoodA(int node)
{
    if (goodA[node]) return true;
    vis[node] = true;

    bool ok = false;
    for (int next : adj[node])
    {
        if (vis[next]) continue;
        ok = ok || reachGoodA(next);
    }

    return ok;
}

bool reachGoodB(int node)
{
    if (goodB[node]) return true;
    vis[node] = true;

    bool ok = false;
    for (int next : adj[node])
    {
        if (vis[next]) continue;
        ok = ok || reachGoodB(next);
    }

    return ok;
}

std::vector<int> who_wins(std::vector<int> A, std::vector<int> R, std::vector<int> U, std::vector<int> V) {
    a = A;
    r = R;
    u = U;
    v = V;

    int n = a.size();
    int m = u.size();
    bool simple = true;
    for (int i = 0; i < m; i++)
    {
        if (!(v[i] == u[i] || v[i] == u[i] + 1)) simple = false;
        adj[u[i]].insert(v[i]);
    }

    std::vector<int> res(a.size());


    bool allA = true;
    bool allB = true;
    for (int i = 0; i < n; i++)
    {
        if (a[i] == 1) allB = false;
        if (a[i] == 0) allA = false;
    }
    //cout << simple << endl;
    if (simple)
    {
        for (int i = 0; i < n; i++)
        {
            int cur = i;
            bool good = false;
            int travelled = 0;
            while (travelled < n)
            {
                if (a[cur] == 1)
                {
                    if (r[cur] == 1)
                    {
                        if (adj[cur].find(cur) != adj[cur].end())
                        {
                            good = true;
                            break;
                        }
                    }

                    for (int next : adj[cur])
                    {
                        if (next != cur)
                        {
                            cur = next;
                            break;
                        }
                    }
                } else
                {
                    if (r[cur] != 1)
                    {
                        if (adj[cur].find(cur) != adj[cur].end())
                        {
                            break;
                        }
                    }

                    for (int next : adj[cur])
                    {
                        if (next != cur)
                        {
                            cur = next;
                            break;
                        }
                    }
                }

                travelled++;
            }

            if (r[cur]) good = true;
            res[i] = good;
        }

        return res;
    } else if (allA)
    {
        for (int i = 0; i < n; i++)
        {
            if (!in[i]) dfs(i);
        }

        for (int i = 0; i < n; i++) res[i] = reachGoodA(i);

        return res;
    } else if (allB)
    {
        for (int i = 0; i < n; i++) if (r[i]) miss[i] = true;

        for (int i = 0; i < n; i++)
        {
            if (!miss[i] && !in[i]) dfs(i);
        }

        for (int i = 0; i < n; i++) res[i] = reachGoodB(i);

        return res;
    }

	return res;
}

/*
10 12
1 1 1 1 1 1 1 1 1 1
0 0 1 0 0 0 1 0 0 0
0 1
1 2
2 1
1 3
1 4
4 5
5 4
6 6
7 7
3 3
8 9
9 8
*/

• Subtask 1: 5 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 11
• Subtask 4: 0 / 11
• Subtask 5: 0 / 12
• Subtask 6: 0 / 51