Submission #453307

#	Time	Username	Problem	Language	Result	Execution time	Memory
453307		Evirir	Bridges (APIO19_bridges)	C++17	100 / 100	2981 ms	9680 KiB

bridges

#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;

#pragma GCC optimize("O3")
#define watch(x) cout<<(#x)<<"="<<(x)<<'\n'
#define mset(d,val) memset(d,val,sizeof(d))
#define setp(x) cout<<fixed<<setprecision(x)
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define forn(i,a,b) for(int i=(a);i<(b);i++)
#define fore(i,a,b) for(int i=(a);i<=(b);i++)
#define pb push_back
#define F first
#define S second
#define fbo find_by_order
#define ook order_of_key
typedef long long ll;
typedef long double ld;
typedef pair<int,int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
//template<typename T>
//using pbds = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
void SD(int t=0){ cout<<"PASSED "<<t<<endl; }
const ll INF = ll(1e18);
const int MOD = 998244353;

const bool DEBUG = 0;
const int MAXN = 50005;
const int MAXM = 100005;
const int MAXQ = 100005;

struct Edge
{
	int u,v; int w;
	bool operator<(const Edge &e){ return w<e.w; }
};

struct DSU
{
	struct Node{ int p; int sz; };
	vector<Node> dsu; int cc;
	vector<pair<int,Node>> upd; // (v,(p,sz))
	DSU(int n){ dsu.resize(n); cc=n; upd.clear();
		forn(i,0,n) dsu[i]={i,1};
	}
	inline int rt(int u){ return u==dsu[u].p ? u : rt(dsu[u].p); }
	inline bool sameset(int u, int v){ return rt(u)==rt(v); }
	void merge(int u, int v){
		u=rt(u); v=rt(v);
		if(u==v) return;
		if(dsu[u].sz<dsu[v].sz) swap(u,v);
		upd.pb({v,dsu[v]});
		dsu[v].p=u;
		dsu[u].sz+=dsu[v].sz;
		cc--;
	}
	void undo()
	{
		assert(!upd.empty());
		auto u=upd.back();
		int p=dsu[u.F].p;
		dsu[p].sz-=u.S.sz;
		dsu[u.F]=u.S;
		upd.pop_back();
	}
	inline Node& operator[](int u){ return dsu[u]; }
};

int n,m,Q;
vector<Edge> edges;
vector<pair<ii,int>> queries; //(node,weight), time
vector<pair<ii,int>> updates; //(id,weight), time
int ans[MAXQ];
bool chg[MAXM];
int neww[MAXM];

bool cmpw(pair<ii,int> &a, pair<ii,int> &b){ return a.F.S>b.F.S; }
void process()
{
	vector<Edge> fixed;
	reverse(all(updates));
	forn(i,0,m)
	{
		if(!chg[i]) fixed.pb(edges[i]);
		else updates.pb({{i,edges[i].w},-1});
	}
	sort(all(fixed));
	reverse(all(updates));
	sort(all(queries),cmpw);
	
	DSU dsu(n);
	
	// large w to small w
	for(auto q: queries)
	{
		int u=q.F.F; int w=q.F.S; int qtime=q.S;
		while(!fixed.empty() && fixed.back().w>=w)
		{
			dsu.merge(fixed.back().u, fixed.back().v);
			fixed.pop_back();
		}
		
		for(auto upd: updates)
		{
			if(upd.S>qtime) break;
			int id=upd.F.F;
			neww[id]=upd.F.S;
		}
		
		int updcnt=0;
		for(auto upd: updates)
		{
			if(upd.S>qtime) break;
			int id=upd.F.F;
			if(neww[id]>=w)
			{
				if(dsu.sameset(edges[id].u, edges[id].v)) continue;
				dsu.merge(edges[id].u, edges[id].v);
				updcnt++;
			}
		}
		
		ans[qtime]=dsu[dsu.rt(u)].sz;
		
		while(updcnt--) dsu.undo();
	}
	
	for(auto upd: updates)
	{
		chg[upd.F.F]=0;
		edges[upd.F.F].w=upd.F.S;
	}
	queries.clear();
	updates.clear();
}

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	
	cin>>n>>m;
	forn(i,0,m)
	{
		int u,v; int w; cin>>u>>v>>w; u--; v--;
		edges.pb({u,v,w});
	}
	
	cin>>Q;
	forn(i,0,Q) ans[i]=-1;
	
	int qcnt=0;
	forn(i,0,Q)
	{
		int t; cin>>t;
		if(t==1)
		{
			int id; int w; cin>>id>>w; id--;
			updates.pb({{id,w},i});
			chg[id]=1;
		}
		else
		{
			int u; int w; cin>>u>>w; u--;
			queries.pb({{u,w},i});
		}
		
		qcnt++;
		if(qcnt>=1000 || i==Q-1)
		{
			process();
			qcnt=0;
		}
	}
	
	forn(i,0,Q)
	{
		if(ans[i]!=-1) 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