Submission #166487

#	Time	Username	Problem	Language	Result	Execution time	Memory
166487		Feeder	Bridges (APIO19_bridges)	C++11	59 / 100	3028 ms	8140 KiB

bridges

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

int par[50001], sz[50001], rnk[50001];

int findp(int x){
	return x == par[x] ? x : findp(par[x]);
}

void merge(int x, int y){
	x = findp(x), y = findp(y);
	if(x == y) return;
	if(rnk[x] < rnk[y]) swap(x, y);
	par[y] = x;
	if(rnk[x] == rnk[y]) rnk[x]++;
	sz[x] += sz[y];
}

void split(int x, int y, int w){
	if(w > 0) rnk[x]--;
	else w = -w;
	par[y] = y;
	sz[x] = w;
}

int n, m, a, b, w, q, t, rt, edgea[100001], edgeb[100001], warr[100001], ans[100001];
set<tuple<int, int> > edgelist;
vector<tuple<int, int, int> > uvec; // query, bridge, weight
vector<tuple<int, int, int> > qvec; // weight, query, island
int qcnt = 0;
int cbridges[100001];

void findans(int qnum){
	//cout << "findans: " << qnum << endl;
	vector<tuple<int, int, int> > st;
	vector<int> vec;
	int qw, qi, qq;
	tie(qw, qq, qi) = qvec[qnum];
	for(int i=int(uvec.size())-1; i>=0; i--){
		if(get<0>(uvec[i]) > qq) continue;
		int bnum = get<1>(uvec[i]);
		w = get<2>(uvec[i]);
		if(cbridges[bnum] == 2) continue;
		cbridges[bnum] = 2;
		vec.push_back(bnum);
		if(w < qw) continue;
		a = edgea[bnum], b = edgeb[bnum];
		a = findp(a), b = findp(b);
		//cout << a << ' ' << b << ' ' << w << endl;
		if(a == b) continue;
		if(rnk[a] < rnk[b]) swap(a, b);
		if(rnk[a] == rnk[b]) st.emplace_back(a, b, sz[a]);
		else st.emplace_back(a, b, -sz[a]);
		merge(a, b);
	}
	for(auto i:vec) cbridges[i] = 1;
	ans[qq] = sz[findp(qi)];
	for(int i=int(st.size())-1; i>=0; i--){
		tie(a, b, w) = st[i];
		split(a, b, w);
	}
}
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> m;
	for(int i=1; i<=m; i++){
		cin >> edgea[i] >> edgeb[i] >> w;
		edgelist.insert(make_tuple(-w, i));
		warr[i] = w;
	}
	
	cin >> q;
	fill(ans, ans + q, -1);
	rt = 500;
	for(int i=0; i<q; i++){
		cin >> t >> a >> b;
		if(t == 1){
			uvec.emplace_back(i, a, b);
			if(!cbridges[a]){
				cbridges[a] = 1;
				uvec.emplace_back(-1, a, warr[a]);
			}
		}
		else qvec.emplace_back(b, i, a);
		if(i % rt != rt - 1 && i != q - 1) continue;
		
		qcnt = int(qvec.size()) - 1;
		sort(qvec.begin(), qvec.end());
		sort(uvec.begin(), uvec.end());
		for(int j=1; j<=n; j++) par[j] = j;
		fill(sz + 1, sz + n + 1, 1);
		fill(rnk + 1, rnk + n + 1, 0);
		for(auto it:edgelist){
			tie(w, a) = it;
			int prew = -w, prea = a;
			while(qcnt >= 0 && get<0>(qvec[qcnt]) > prew){
				findans(qcnt);
				qcnt--;
			}
			if(cbridges[prea]) continue;
			b = edgeb[prea];
			a = edgea[prea];
			//cout << "merge: " << a << ' ' << b << endl;
			merge(a, b);
		}
		while(qcnt >= 0){
			findans(qcnt);
			qcnt--;
		}
		
		for(int j=int(uvec.size())-1; j>=0; j--){
			b = get<1>(uvec[j]), w = get<2>(uvec[j]);
			if(cbridges[b] == 0) continue;
			edgelist.erase(make_tuple(-warr[b], b));
			edgelist.insert(make_tuple(-w, b));
			warr[b] = w;
			cbridges[b] = 0;
		}
		
		uvec.clear();
		qvec.clear();
	}
	for(int i=0; i<q; i++){
		if(ans[i] != -1) cout << ans[i] << '\n';
	}
}

• Subtask 1: 13 / 13
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 0 / 14
• Subtask 5: 13 / 13
• Subtask 6: 0 / 27