Submission #132101

#	Time	Username	Problem	Language	Result	Execution time	Memory
132101		MvC	Bridges (APIO19_bridges)	C++11	43 / 100	855 ms	14452 KiB

bridges

#pragma GCC target("avx2")
#pragma GCC optimization("O3")
#pragma GCC optimization("unroll-loops")
#include<bits/stdc++.h>
//#include "job.h"
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define mkp make_pair
#define in insert
#define er erase
#define fd find
#define fr first
#define sc second
typedef long long ll;
typedef long double ld;
const ll INF=0x3f3f3f3f3f3f3f3f;
const ll llinf=(1LL<<62);
const int inf=(1<<30);
const int nmax=1e5+50;
const int mmax=1e3+50;
const int mod=1e9+7;
using namespace std;
int x,y,z,nr,vz[mmax],q,i,t,n,m,vl[nmax],st[4*nmax],l,r,mid,lb,rb,p[nmax],sz[nmax],ans[nmax],j;
vector<pair<pair<int,int>,int> >e;
vector<pair<int,pair<int,int> > >ne,qr;
vector<int>a[nmax];
void dfs(int x,int z)
{
	vz[x]=1;
	nr++;
	for(int i=0;i<a[x].size();i++)
	{
		int y=a[x][i],u=x^e[y].fr.fr^e[y].fr.sc;
		if(vz[u] || e[y].sc<z)continue;
		dfs(u,z);
	}
}
void upd(int nod,int l,int r,int p)
{
	if(l==r)
	{
		st[nod]=vl[l];
		return;
	}
	int mid=(l+r)/2;
	if(p<=mid)upd(2*nod,l,mid,p);
	else upd(2*nod+1,mid+1,r,p);
	st[nod]=min(st[2*nod],st[2*nod+1]);
}
int qry(int nod,int l,int r,int tl,int tr)
{
	if(tr<l || tl>r)return inf;
	if(tl<=l && r<=tr)return st[nod];
	int mid=(l+r)/2;
	return min(qry(2*nod,l,mid,tl,tr),qry(2*nod+1,mid+1,r,tl,tr));
}
int fnd(int x)
{
    if(p[x]==x)return x;
    return p[x]=fnd(p[x]);
}
void uni(int x,int y)
{
    x=fnd(x);
    y=fnd(y);
    if(x!=y)
    {
        if(sz[x]<sz[y])swap(x,y);
        p[y]=x;
        sz[x]+=sz[y];
    }
}
int main()
{
	//freopen("sol.in","r",stdin);
	//freopen("sol.out","w",stdout);
	//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
	ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
	cin>>n>>m;
	for(i=1;i<=4*n;i++)st[i]=inf;
	for(i=1;i<=m;i++)
	{
		cin>>x>>y>>z;
		a[x].pb(i-1);
		a[y].pb(i-1);
		e.pb(mkp(mkp(x,y),z));
		vl[x]=z;
		upd(1,1,n,x);
	}
	cin>>q;
	if(n<=1000 && m<=1000 && q<=10000)
	{
		while(q--)
		{
			cin>>t>>x>>z;
			if(t==1)
			{
				x--;
				e[x].sc=z;
			}
			else
			{
				memset(vz,0,sizeof(vz));
				nr=0;
				dfs(x,z);
				cout<<nr<<'\n';
			}
		}
		return 0;
	}
	else if(m==n-1)
	{
		while(q--)
		{
			cin>>t>>x>>z;
			if(t==1)
			{
				x--;
				e[x].sc=z;
				vl[e[x].fr.fr]=z;
				upd(1,1,n,e[x].fr.fr);
			}
			else
			{
				l=1,r=x-1,lb=-1;
				while(l<=r)
				{
					mid=(l+r)/2;
					if(qry(1,1,n,mid,x-1)>=z)lb=mid,r=mid-1;
					else l=mid+1;
				}
				l=x,r=n-1,rb=-1;
				while(l<=r)
				{
					mid=(l+r)/2;
					if(qry(1,1,n,x,mid)>=z)rb=mid,l=mid+1;
					else r=mid-1;
				}
				if(lb==-1 && rb==-1)cout<<1<<'\n';
				else if(lb==-1)cout<<rb+1-x+1<<'\n';
				else if(rb==-1)cout<<x-lb+1<<'\n';
				else cout<<rb+1-lb+1<<'\n';
			}
		}
	}
	else
	{
		for(i=1;i<=n;i++)
		{
			p[i]=i;
			sz[i]=1;
		}
		for(i=0;i<m;i++)
		{
			ne.pb(mkp(e[i].sc,mkp(e[i].fr.fr,e[i].fr.sc)));
		}
		sort(ne.begin(),ne.end());
		reverse(ne.begin(),ne.end());
		for(i=1;i<=q;i++)
		{
			cin>>t>>x>>z;
			qr.pb(mkp(z,mkp(x,i)));
		}
		sort(qr.begin(),qr.end());
		reverse(qr.begin(),qr.end());
		for(i=0;i<q;i++)
		{
			for(;j<m;j++)
			{
				if(ne[j].fr<qr[i].fr)break;
				uni(ne[j].sc.fr,ne[j].sc.sc);
			}
			ans[qr[i].sc.sc]=sz[fnd(qr[i].sc.fr)];
		}
		for(i=1;i<=q;i++)cout<<ans[i]<<'\n';
	}
    return 0;
}

Compilation message (stderr)

bridges.cpp:2:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization("O3")
 
bridges.cpp:3:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization("unroll-loops")
 
bridges.cpp: In function 'void dfs(int, int)':
bridges.cpp:31:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<a[x].size();i++)
              ~^~~~~~~~~~~~

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