Submission #542443

#	Time	Username	Problem	Language	Result	Execution time	Memory
542443		fcw	Bitaro’s Party (JOI18_bitaro)	C++17	14 / 100	2084 ms	168200 KiB

bitaro

#include <bits/stdc++.h>
#define st first
#define nd second
using lint = int64_t;
constexpr int mod = int(1e9) + 7;
constexpr int inf = 0x3f3f3f3f;
constexpr int ninf = 0xcfcfcfcf;
constexpr lint linf = 0x3f3f3f3f3f3f3f3f;
const long double pi = acosl(-1.0);
// Returns -1 if a < b, 0 if a = b and 1 if a > b.
int cmp_double(double a, double b = 0, double eps = 1e-9) {
	return a + eps > b ? b + eps > a ? 0 : 1 : -1;
}
using namespace std;


int main() {
	cin.tie(nullptr)->sync_with_stdio(false);
	const int SZ = 200;
	int n, m, q;
	cin>>n>>m>>q;
	vector<vector<int>>g(n);
	vector<int>d(n);
	for(int i=0;i<m;i++){
		int a, b;
		cin>>a>>b;
		a--, b--;
		g[a].push_back(b);
		d[b]++;
	}
	vector<vector<pair<int, int>>>prep(n);
	for(int i=0;i<n;i++) prep[i] = {{0, i}};
	// k-th greatest path to vertice v up to k <= sz + 1
	vector<bool>w(n);
	{
		queue<int>qu;
		for(int i=0;i<n;i++) if(!d[i]) qu.push(i);
		while(!qu.empty()){
			int u = qu.front();
			qu.pop();
			for(int v : g[u]){
				d[v]--;
				if(!d[v]) qu.push(v);
				int pu = (int)prep[u].size(), pv = (int)prep[v].size();
				int s = min(pu + pv, SZ);
				vector<pair<int, int>>c(s);
				for(int l=0,r=0,i=0;i<s;i++){
					while(l < pu && w[prep[u][l].nd]) l++;
					while(r < pv && w[prep[v][r].nd]) r++;
					if(l < pu && r < pv){
						if(prep[u][l].st + 1 >= prep[v][r].st){
							c[i] = {prep[u][l].st + 1, prep[u][l].nd}; w[prep[u][l].nd] = 1; l++;
						}
						else{
							c[i] = {prep[v][r].st, prep[v][r].nd}; w[prep[v][r].nd] = 1; r++;
						}
					}
					else if(l < pu){ c[i] = {prep[u][l].st + 1, prep[u][l].nd}; w[prep[u][l].nd] = 1; l++;}
					else if(r < pv){ c[i] = {prep[v][r].st, prep[v][r].nd}; w[prep[v][r].nd] = 1; r++;}
					else{ c.resize(i); break; }
				}
				for(auto [dist, id] : c) w[id] = 0;
				swap(prep[v], c);
			}
		}
	}
	for(int i=0;i<n;i++) w[i] = 0;
	for(int T=0;T<q;T++){
		int u, k;
		cin>>u>>k;
		u--;
		vector<int>skip(k);
		for(int i=0;i<k;i++) cin>>skip[i], skip[i]--;
		for(int v : skip) w[v] = 1;
		if(k >= SZ){
			for(int i=0;i<=u;i++) d[i] = 0;
			for(int i=0;i<=u;i++){
				for(int v : g[i]){
					if(v > u) continue;
					d[v]++;
				}
			}
			queue<int>qu;
			vector<int>dp(u+1, -1);
			for(int i=0;i<=u;i++){
				if(!w[i]) dp[i] = 0;
				if(!d[i]) qu.push(i);
			}
			while(!qu.empty()){
				int cur = qu.front(); qu.pop();
				for(int v : g[cur]){
					if(v > u) continue;
					if(dp[cur] >= 0) dp[v] = max(dp[v], dp[cur] + 1);
					d[v]--;
					if(!d[v]) qu.push(v);
				}
			}
			cout<<dp[u]<<"\n";
		}
		else{
			int ans = -1;
			for(auto [dist, v] : prep[u]){
				if(w[v]) continue;
				ans = dist;
				break;
			}
			cout<<ans<<"\n";
		}
		for(int v : skip) w[v] = 0;
	}






	return 0;
}
/*
[  ]Leu o problema certo???
[  ]Ver se precisa de long long
[  ]Viu o limite dos fors (é n? é m?)
[  ]Tamanho do vetor, será que é 2e5 em vez de 1e5??
[  ]Testar sample
[  ]Testar casos de  borda
[  ]1LL no 1LL << i
[  ]Testar mod (é 1e9+7, mesmo?, será que o mod não ficou negativo?)
*/

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 0 / 86