# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
383449 | thiago4532 | Bitaro’s Party (JOI18_bitaro) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
#pragma GCC optimization ("unroll-loops")
using namespace std;
typedef pair<int, int> pii;
const int maxn = 1e5 + 10;
int n, m, q, dist[maxn], grau[maxn], grau2[maxn];
vector<int> grafo[maxn];
bool mark[maxn], mark2[maxn];
vector<pii> guarda[maxn];
#define gc getchar_unlocked
inline int scan() {
int x = gc(), n = 0;
for(;x < '0' || x > '9'; x = gc()) {}
for(;x >= '0' && x <= '9'; x = gc()) n = 10*n + x - '0';
return n;
}
int main() {
ios::sync_with_stdio(false), cin.tie(0);
n = scan(), m = scan(), q = scan();
int sq = 200;
for (int i = 1; i <= m; i++) {
int a, b;
a = scan(), b = scan();
grafo[a].push_back(b);
grau[b]++;
grau2[b]++;
}
{ // precompute unordered map
queue<int> fila;
for (int i = 1; i <= n; i++) {
guarda[i].push_back({0, i});
if (grau2[i] == 0) fila.push(i);
guarda[i].reserve(sq+1);
}
vector<pii> aux;
aux.reserve(2*sq);
while (!fila.empty()) {
int u = fila.front();
fila.pop();
for(auto& e : guarda[u])
e.first++;
for(auto v : grafo[u]) {
aux.resize(aux2.size() + guarda[v].size());
grau2[v]--;
if (grau2[v] == 0) fila.push(v);
merge(aux2.begin(), aux2.end(),
guarda[v].begin(), guarda[v].end(), aux.begin(), greater<pii>());
guarda[v].clear();
for(auto it = aux.begin(); it != aux.end() && guarda[v].size() <= sq; it++)
if(!mark[it->second]) guarda[v].push_back(*it), mark[it->second] = true;
for (auto e : guarda[v])
mark[e.second] = false;
}
for (auto& e : guarda[u])
e.first--;
}
}
for (int i = 1; i <= q; i++) {
int t, y;
t = scan(), y= scan();
vector<int> query(y);
for (int i = 0; i < y; i++)
query[i] = scan();
if (y >= sq) {
for (int i = 1; i <= n; i++) {
mark[i] = dist[i] = 0;
grau2[i] = grau[i];
}
for (int i = 0; i < y; i++)
mark[query[i]] = true;
queue<int> fila;
for (int i = 1; i <= n; i++)
if (grau2[i] == 0) fila.push(i);
while (!fila.empty()) {
int u = fila.front();
fila.pop();
for(auto v : grafo[u]) {
grau2[v]--;
if (grau2[v] == 0) fila.push(v);
if (dist[u] > 0 || !mark[u])
dist[v] = max(dist[v], dist[u] + 1);
}
}
if (dist[t] == 0 && mark[t]) cout << "-1\n";
else cout << dist[t] << '\n';
} else {
for (int j = 0; j < y; j++)
mark2[query[j]] = true;
int ans = -1;
for (auto it = guarda[t].begin(); it != guarda[t].end(); it++) {
if (!mark2[it->second]) {
ans = it->first;
break;
}
}
for (int j = 0; j < y; j++)
mark2[query[j]] = false;
cout << ans << '\n';
}
}
return 0;
}