Submission #1299177

#	Time	Username	Problem	Language	Result	Execution time	Memory
1299177		trandangquang	Making Friends on Joitter is Fun (JOI20_joitter2)	C++20	0 / 100	5 ms	9784 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<int> in[N],out[N];

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

    if(in[x].count(y)) in[x].erase(y);
    if(out[x].count(y)) out[x].erase(y);
    if(in[y].count(x)) in[y].erase(x);
    if(out[y].count(x)) out[y].erase(x);

    sz[x]+=sz[y];
    par[y]=x;
    for(int i:in[y]){
        in[x].insert(i);
        out[i].erase(y);
        out[i].insert(x);
    }
    in[y].clear();
    for(int i:out[y]){
        out[x].insert(i);
        in[i].erase(y);
        in[i].insert(x);
    }
    out[y].clear();

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

void solve(){
    cin>>n>>m;
    foru(i,1,n){
        sz[i]=1;
    }
    rep(i,m){
        int u,v; cin>>u>>v;
        u=find(u); v=find(v);

        if(!out[u].count(v)){
            in[v].insert(u);
            out[u].insert(v);
            res+=sz[v];
        }

        if(out[v].count(u)){
            unite(u,v);
        }
        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:89:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
joitter2.cpp:90:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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