Submission #551013

#	Time	Username	Problem	Language	Result	Execution time	Memory
551013		valerikk	Bridges (APIO19_bridges)	C++17	100 / 100	2874 ms	10912 KiB

bridges

#include <bits/stdc++.h>

using namespace std;

const int N = 50057;
const int M = 100123;
const int B = 500;

int n, m;
int a[M], b[M], c[M];
int Q;
int t[M], x[M], y[M];

int dsu[N];
int sz[N];

vector<int> g[N];
bool used[N];

int ans[M];

int e[M];
bool inb[M];
bool was[M];
int q[N];

int get(int i) {
	return i == dsu[i] ? i : dsu[i] = get(dsu[i]);
}

void merge(int i, int j) {
	i = get(i);
	j = get(j);
	
	if (i == j) 
		return;

	if (sz[i] > sz[j]) 
		swap(i, j);

	sz[j] += sz[i];
	dsu[i] = j;
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin >> n >> m;
	for (int i = 0; i < m; ++i) {
		cin >> a[i] >> b[i] >> c[i];
		--a[i];
		--b[i];
	}

	vector<int> ord(m);
	iota(ord.begin(), ord.end(), 0);
	sort(begin(ord), end(ord), [&](const int &i, const int &j) {
		return c[i] > c[j];
	});

	cin >> Q;
	for (int i = 0; i < Q; ++i) {
		cin >> t[i] >> x[i] >> y[i];
		--x[i];
	}

	for (int bl = 0; bl < Q; bl += B) {
		int br = min(Q, bl + B);

		for (int i = bl; i < br; ++i) {
			if (t[i] == 1) 
				inb[x[i]] = true;
		}

		int esz = 0;
		
		for (int i : ord) {
			if (!inb[i]) 
				e[esz++] = i;
		}

		vector<int> p;
		
		for (int i = bl; i < br; ++i) {
			if (t[i] == 2) 
				p.push_back(i);
		}

		sort(begin(p), end(p), [&](const int &i, const int &j) {
			return y[i] > y[j];
		});

		for (int i = 0; i < n; ++i) {
			dsu[i] = i;
			sz[i] = 1;
		}

		int eptr = 0;

		for (int i : p) {
			while (eptr < esz && c[e[eptr]] >= y[i]) {
				merge(a[e[eptr]], b[e[eptr]]);
				++eptr;
			}

			// cout << "i " << i << endl;
			for (int j = i - 1; j >= bl; --j) {
				if (t[j] == 1 && !was[x[j]]) {
					if (y[j] >= y[i]) {
						// cout << "add1 " << j << " " << a[x[j]] << " " << b[x[j]] << " " << y[j] << endl;
						g[get(a[x[j]])].emplace_back(get(b[x[j]]));
						g[get(b[x[j]])].emplace_back(get(a[x[j]]));
					}
					was[x[j]] = true;
				}
			}
			for (int j = br - 1; j > i; --j) {
				if (t[j] == 1 && !was[x[j]]) {
					if (c[x[j]] >= y[i]) {
						// cout << "add2 " << j << " " << x[j] << " " << a[x[j]] << " " << b[x[j]] << " " << c[x[j]] << endl;
						g[get(a[x[j]])].emplace_back(get(b[x[j]]));
						g[get(b[x[j]])].emplace_back(get(a[x[j]]));
					}
					was[x[j]] = true;
				}
			}

			int qh = 0, qt = 0;
			
			q[qt++] = get(x[i]);
			used[get(x[i])] = true;

			while (qh < qt) {
				int v = q[qh++];

				ans[i] += sz[v];

				for (int u : g[v]) {
					if (!used[u]) {
						used[u] = true;
						q[qt++] = u;
					}
				}
			}

			used[get(x[i])] = false;

			for (int j = i - 1; j >= bl; --j) {
				if (t[j] == 1 && was[x[j]]) {
					// if (y[j] >= y[i]) {
						// cout << "remove1 " << j << " " << a[x[j]] << " " << b[x[j]] << " " << y[j] << endl;
						used[get(a[x[j]])] = false;
						used[get(b[x[j]])] = false;
						g[get(a[x[j]])].clear();
						g[get(b[x[j]])].clear();
					// }
					was[x[j]] = false;
				}
			}
			for (int j = br - 1; j > i; --j) {
				if (t[j] == 1 && was[x[j]]) {
					// if (c[x[j]] >= y[i]) {
						// cout << "remove2 " << j << " " << a[x[j]] << " " << b[x[j]] << " " << c[x[j]] << endl;
						used[get(a[x[j]])] = false;
						used[get(b[x[j]])] = false;
						g[get(a[x[j]])].clear();
						g[get(b[x[j]])].clear();
					// }
					was[x[j]] = false;
				}
			}
		}

		for (int i = bl; i < br; ++i) {
			if (t[i] == 1) {
				inb[x[i]] = false;
				c[x[i]] = y[i];
			}
		}
		sort(ord.begin(), ord.end(), [&](const int &i, const int &j) {
			return c[i] > c[j];
		});
	}

	for (int i = 0; i < Q; ++i) {
		if (t[i] == 2) {
			cout << ans[i] << "\n";
		}
	}

	return 0;
}

• Subtask 1: 13 / 13
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 14 / 14
• Subtask 5: 13 / 13
• Subtask 6: 27 / 27