Submission #229276

#	Time	Username	Problem	Language	Result	Execution time	Memory
229276		534351	Bulb Game (FXCUP4_bulb)	C++17	0 / 100	5 ms	512 KiB

bulb

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

using namespace std;

template<class T, class U>
void ckmin(T &a, U b)
{
    if (a > b) a = b;
}

template<class T, class U>
void ckmax(T &a, U b)
{
    if (a < b) a = b;
}

#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define SZ(x) ((int) (x).size())
#define ALL(x) (x).begin(), (x).end()
#define FOR(i, a, b) for (auto i = (a); i < (b); i++)
#define FORD(i, a, b) for (auto i = (a) - 1; i >= (b); i--)

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpi;
typedef vector<pll> vpl;

const int MAXN = 300013;

int N;
pii child[MAXN];
bitset<MAXN> bad, onpath;
bool flag; //are offpath banned?
vi path;

//-1 if it's red (so a result of 1 / a win)
void dfs(int u, vi dif)
{
    if (child[u].fi < 0)
    {
        if (child[u].fi == -2)
        {
            // cerr << "uhoh " << u << endl;
            if (SZ(dif) == 2)
            {
                //u and v are not allowed.
                bad[dif[0]] = true;
                bad[dif[1]] = true;
            }
            else if (SZ(dif) == 1)
            {
                bad[dif[0]] = true;
                flag = true;
            }
            else
            {
                assert(false);
            }
        }
    }
    else
    {
        dfs(child[u].fi, dif);
    }
    if (SZ(dif) < 2)
    {
        if (child[u].se < 0)
        {
            if (SZ(dif) == 1)
            {
                bad[u] = true;
                bad[dif[0]] = true;
            }
            else if (dif.empty())
            {
                bad[u] = true;
                flag = true;
            }
            else
            {
                assert(false);
            }
        }
        else
        {
            dif.PB(u);
            dfs(child[u].se, dif);
        }
    }
}

int FindWinner(int T, std::vector<int> L, std::vector<int> R)
{
    N = SZ(L);
    FOR(i, 0, N)
    {
        child[i] = {L[i], R[i]};
    }
    path.PB(0);
    while(path.back() >= 0)
    {
        path.PB(child[path.back()].fi);
    }
    if (path.back() == -2)
    {
        return 0;
    }
    path.pop_back();
    for (int u : path)
    {
        onpath[u] = true;
    }
    dfs(0, vi(0));
    // cerr << "flag ? " << flag << endl;
    FOR(u, 0, N)
    {
        if (onpath[u])
        {
            if (!bad[u]) return 1;
        }
        else
        {
            if (!bad[u] && !flag) return 1;
        }
    }
    return 0;
    //for you to be able to win with switching x:
    //if x is not the direct left path, eh it's kinda pointless then.
    //T doesn't matter?? you literally just like, try it to see if there's a move 0 can choose
    //check if there's a node you can toggle such that everybody remains safe.
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 25
• Subtask 3: 0 / 64