Submission #1299293

#	Time	Username	Problem	Language	Result	Execution time	Memory
1299293		trandangquang	Making Friends on Joitter is Fun (JOI20_joitter2)	C++20	0 / 100	5 ms	9796 KiB

joitter2

#include<bits/stdc++.h>
using namespace std;

#define foru(i,a,b) for(int i=(a); i<=(b); ++i)
#define ford(i,a,b) for(int i=(a); i>=(b); --i)
#define rep(i,a) for(int i=0; i<(a); ++i)
#define sz(a) (int)(a).size()
#define all(a) (a).begin(),(a).end()
#define bit(s,i) (((s)>>(i))&1)
#define ii pair<int,int>
#define vi vector<int>
#define vii vector<ii>
#define fi first
#define se second
#define ll long long
#define eb emplace_back
#define pb push_back
#define __builtin_popcount __builtin_popcountll
#define _ << " " <<

template <class X, class Y> bool maxi(X &x, Y y){return x<y?x=y,true:false;}
template <class X, class Y> bool mini(X &x, Y y){return x>y?x=y,true:false;}

const int N=1e5+5;

int n,m,par[N],sz[N]; ll res;
set<ii> in[N];
set<int> out[N];
vector<ii> mer;

int find(int x){
    return par[x]==0 ? x : par[x]=find(par[x]);
}

void unite(int x, int y){
    x=find(x); y=find(y);
    if(x==y) return;

    if(sz(in[x])+sz(out[x]) < sz(in[y])+sz(out[y])) swap(x,y);

    res-=1LL*sz[x]*(sz[x]-1) + 1LL*sz[x]*sz(in[x]);
    res-=1LL*sz[y]*(sz[y]-1) + 1LL*sz[y]*sz(in[y]);

    par[y]=x;
    sz[x]+=sz[y];

    /// delete between 2 components x and y
    // x -> y
    out[x].erase(y);

    vii del;
    for(auto [cc,v]:in[y]){
        if(cc==x) del.eb(cc,v);
    }
    for(auto i:del) in[y].erase(i);

    // y -> x
    out[y].erase(x);
    auto it=in[x].lower_bound(ii(y,0));
    while(it!=in[x].end() && it->fi==y){
        it=in[x].erase(it);
    }

    /// push next merge
    for(auto [cc,v]:in[y]){
        if(out[x].count(cc)){
            mer.eb(cc,x);
        }
    }
    for(int cc:out[y]){
        if(out[cc].count(x)){
            mer.eb(cc,x);
        }
    }

    /// adjust out[y]
    for(int cc:out[y]){
        vi idx;
        auto it=in[cc].lower_bound(ii(y,0));
        while(it!=in[cc].end() && it->fi==y){
            idx.eb(it->se);
            it=in[cc].erase(it);
        }
        for(int i:idx){
//                cout<<cc _ x _ i<<'\n';
            in[cc].insert(ii(x,i));
        }
    }
    for(auto i:in[y]){
        out[i.fi].erase(y);
        out[i.fi].insert(x);
    }

    for(auto i:in[y]) in[x].insert(i);
    for(int i:out[y]) out[x].insert(i);
    in[y].clear();
    out[y].clear();

    res+=1LL*sz[x]*sz(in[x]) + 1LL*sz[x]*(sz[x]-1);
}

void solve(){
    cin>>n>>m;
    foru(i,1,n) sz[i]=1;
    foru(im,1,m){
        int u,v; cin>>u>>v;
        if(find(u)!=find(v)){
            if(!out[find(u)].count(find(v))){
                out[find(u)].insert(find(v));
                in[find(v)].insert(ii(find(u),u));
                res+=sz[find(v)];
            }
            if(out[find(v)].count(find(u))){
                mer.eb(u,v);
            }
        }

        while(sz(mer)){
            auto [x,y]=mer.back(); mer.pop_back();
//            cout<<x _ y _ im<<'\n';
            unite(x,y);
        }
        cout<<res<<'\n';
    }

}

int32_t main(){
    #define task "test"
    if(fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    cin.tie(0)->sync_with_stdio(0);

    int tc=1; //cin>>tc;
    foru(i,1,tc){
        solve();
    }
}

Compilation message (stderr)

joitter2.cpp: In function 'int32_t main()':
joitter2.cpp:131:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  131 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
joitter2.cpp:132:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  132 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 1
• Subtask 2: 0 / 16
• Subtask 3: 0 / 83