Submission #1071087

#	Time	Username	Problem	Language	Result	Execution time	Memory
1071087		kustizus	Bridges (APIO19_bridges)	C++17	100 / 100	2484 ms	9208 KiB

bridges

// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
// #define int long long
#define all(v) v.begin(),v.end()
using namespace std;
mt19937_64 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
const int N=1e5;
int n,m,q,u[N+5],v[N+5],d[N+5],ty[N+5],x[N+5],y[N+5],ans[N+5],tr[N+5];
bool ok,use[N+5];
void Update(int i, int j){
    for (int k=i;k<=j;++k)
        if (ty[k]==1) d[x[k]]=y[k];
}
struct DSU_rollback{
    int ds[N+5];
    vector <pair<int,int>> history;
    void Reset(){
        for (int i=1;i<=n;++i) ds[i]=-1;
        history.clear();
    }
    int Get(int idx){
        return ds[idx]<0 ? idx : Get(ds[idx]);
    }
    void Join(int u, int v){
        u=Get(u);
        v=Get(v);
        if (u==v) return;
        if (ds[u]>ds[v]) swap(u,v);
        if (ok) history.push_back({v,ds[v]});
        ds[u]+=ds[v];
        ds[v]=u;
    }
    void RollBack(int sz){
        while (history.size()>sz){
            ds[ds[history.back().first]]-=history.back().second;
            ds[history.back().first]=history.back().second;
            history.pop_back();
        }
    }
} dsu;
void Sol(int l, int r){
    vector <int> before_edge,now_edge,query,qr1;
    for (int i=l;i<=r;++i)
        if (ty[i]==1){
            use[x[i]]=true;
            qr1.push_back(i);
        }
        else query.push_back(i);
    for (int i=1;i<=m;++i)
        if (!use[i]) before_edge.push_back(i);
        else now_edge.push_back(i);
    sort(all(before_edge),[&](int x, int y){return d[x]>d[y];});
    sort(all(query),[&](int a, int b){return y[a]>y[b];});
    dsu.Reset();
    int pointer=0;
    for (int i=l;i<=r;++i) tr[x[i]]=d[x[i]];
    for (int pos : query){
        while (pointer<before_edge.size() && d[before_edge[pointer]]>=y[pos]){
            ok=false;
            dsu.Join(u[before_edge[pointer]],v[before_edge[pointer]]);
            ++pointer;
        }
        ok=true;
        int size_before=dsu.history.size();
        for (int i : qr1)
            if (i<pos)
                tr[x[i]]=y[i];
            else break;
        for (int i : now_edge)
            if (tr[i]>=y[pos])
                dsu.Join(u[i],v[i]);
        for (int i : qr1)
            if (i<pos)
                tr[x[i]]=d[x[i]];
            else break;
        ans[pos]=-dsu.ds[dsu.Get(x[pos])];
        dsu.RollBack(size_before);
    }
    for (int x : now_edge) use[x]=false;
}
void Solve(){
    cin>>n>>m;
    for (int i=1;i<=m;++i) cin>>u[i]>>v[i]>>d[i];
    cin>>q;
    for (int i=1;i<=q;++i) cin>>ty[i]>>x[i]>>y[i];
    int bl=500;
    for (int i=1;i<=q;i+=bl){
        int j=min(q,i+bl-1);
        Sol(i,j);
        Update(i,j);
    }
    for (int i=1;i<=q;++i)
        if (ty[i]==2) cout<<ans[i]<<"\n";
}
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    // freopen ("FILE.INP","r",stdin);
    // freopen ("FILE.OUT","w",stdout);
    int t=1;
    while (t--) Solve();
    cerr<<"\nTIME: "<<1000*clock()/CLOCKS_PER_SEC<<"ms\n";
}

Compilation message (stderr)

bridges.cpp: In member function 'void DSU_rollback::RollBack(int)':
bridges.cpp:35:30: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   35 |         while (history.size()>sz){
      |                ~~~~~~~~~~~~~~^~~
bridges.cpp: In function 'void Sol(int, int)':
bridges.cpp:59:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |         while (pointer<before_edge.size() && d[before_edge[pointer]]>=y[pos]){
      |                ~~~~~~~^~~~~~~~~~~~~~~~~~~

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