Submission #649067

#	Time	Username	Problem	Language	Result	Execution time	Memory
649067		ToroTN	Bridges (APIO19_bridges)	C++14	100 / 100	2505 ms	15696 KiB

bridges

#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3")
#pragma GCC target ("sse4")
#define X first
#define Y second
#define pb push_back
set<pair<int,int> > s;
vector<pair<int,int> > g;
vector<tuple<int,int,int> > answer;
stack<pair<int,int> > stk;
int n,m,num=1200,t,u[100005],v[100005],w[100005],e[100005];
int op[100005],a[100005],b[100005],mx=-1,group[100005],it1,it2;
int p[50005],sz[50005],e2[100005],ans[100005],hsh[100005];
int l,r,pasin,nathan,bothtoq,uaytaq;
int f(int a)
{
    while(p[a]!=a)a=p[a];
    return a;
}
stack<int> sack;
void un(int b,int c)
{
    if(b>c)swap(b,c);
    sz[c]+=sz[b];
    p[b]=c;
}
void rollback(int x) {
	while (sack.size() > x) {
		int k = sack.top();
		sack.pop();
		sz[p[k]] -= sz[k];
		p[k] = k;
	}
}

void iterate()
{
    for(auto it=s.begin();it!=s.end();it++)
    {
        printf("krit=%d %d\n",(*it).X,(*it).Y);
    }
    printf("\n");
}
int main()
{
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d%d",&u[i],&v[i],&w[i]);
        e[i]=w[i];
        s.insert({e[i],i});
    }
    scanf("%d",&t);
    for(int i=1;i<=t;i++)
    {
        scanf("%d%d%d",&op[i],&a[i],&b[i]);
        group[i]=(i-1)/num+1;
        mx=max(mx,group[i]);
    }
    for(int i=1;i<=mx;i++)
    {
        l=(i-1)*num+1;
        r=min(t,i*num);
        g.clear();
        answer.clear();
        if(s.size()!=0)
        for(auto it=s.begin();it!=s.end();it++)
        {
            stk.push({(*it).X,(*it).Y});
        }
        while(!stk.empty())
        {
            g.pb({stk.top().X,stk.top().Y});
            stk.pop();
        }
        for(int j=1;j<=m;j++)hsh[j]=0;
        for(int j=l;j<=r;j++)
        {
            if(op[j]==2)
            {
                answer.pb({b[j],a[j],j});
            }else ++hsh[a[j]];
        }
        sort(answer.rbegin(),answer.rend());
        it1=0,it2=0;
        for(int j=1;j<=n;j++)p[j]=j,sz[j]=1;
        for(int j=1;j<=m;j++)e2[j]=e[j];
        while(it2<(int)answer.size())
        {
            auto [w2,node,idx]=answer[it2];
            if(it1<(int)g.size())
            {
                int w=g[it1].X,edge=g[it1].Y;
                if(w>=w2)
                {
                    ///////////
                    bothtoq=f(u[edge]);
                    uaytaq=f(v[edge]);
                    if(bothtoq!=uaytaq&&hsh[edge]==0)
                    {
                        un(bothtoq,uaytaq);
                    }
                    //////////
                    ++it1;
                    continue;
                }
            }
            for(int j=l;j<=r;j++)
            {
                if(op[j]==1&&j<idx)
                {
                    e2[a[j]]=b[j];
                }
            }
            for(int j=l;j<=r;j++)
            {
                if(op[j]==1)
                {
                    if(e2[a[j]]>=b[idx])
                    {
                        pasin=f(u[a[j]]);
                        nathan=f(v[a[j]]);
                        if(pasin!=nathan)
                        {
                            if(sz[pasin]>sz[nathan])swap(pasin,nathan);
                            sack.push(pasin);
                            sz[nathan]+=sz[pasin];
                            p[pasin]=nathan;
                        }
                    }
                }
            }
            ans[idx]=sz[f(node)];
            for(int j=l;j<=r;j++)
            {
                if(op[j]==1&&j<idx)e2[a[j]]=e[a[j]];
            }
            while(!sack.empty())
            {
                sz[p[sack.top()]]-=sz[sack.top()];
                p[sack.top()]=sack.top();
                sack.pop();
            }
            ++it2;
        }
        for(int j=l;j<=r;j++)
        {
            if(op[j]==1)
            {
                if(s.find({e[a[j]],a[j]})!=s.end())
                {
                    s.erase(s.find({e[a[j]],a[j]}));
                }
                e[a[j]]=b[j];
                s.insert({e[a[j]],a[j]});
            }
        }
    }
    for(int i=1;i<=t;i++)
    {
        if(op[i]==2)printf("%d\n",ans[i]);
    }
}

Compilation message (stderr)

bridges.cpp: In function 'void rollback(int)':
bridges.cpp:29:21: warning: comparison of integer expressions of different signedness: 'std::stack<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   29 |  while (sack.size() > x) {
      |         ~~~~~~~~~~~~^~~
bridges.cpp: In function 'int main()':
bridges.cpp:91:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   91 |             auto [w2,node,idx]=answer[it2];
      |                  ^
bridges.cpp:47:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~
bridges.cpp:50:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |         scanf("%d%d%d",&u[i],&v[i],&w[i]);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
bridges.cpp:54:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   54 |     scanf("%d",&t);
      |     ~~~~~^~~~~~~~~
bridges.cpp:57:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |         scanf("%d%d%d",&op[i],&a[i],&b[i]);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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