Submission #1299185

#	Time	Username	Problem	Language	Result	Execution time	Memory
1299185		trandangquang	Making Friends on Joitter is Fun (JOI20_joitter2)	C++20	0 / 100	3 ms	5184 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=101010;

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

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

    vi del;
    for(int i:in[x]){
        if(find(i)==y) del.eb(i);
    }
    for(int i:del) in[x].erase(i);
    del.clear();

    for(int i:in[y]){
        if(find(i)==x) del.eb(i);
    }
    for(int i:del) in[y].erase(i);
    del.clear();

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

    for(int i:in[y]){
        in[x].insert(i);
    }
    in[y].clear();

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

void solve(){
    cin>>n>>m;
    foru(i,1,n) sz[i]=1;
    rep(i,m){
        int u,v; cin>>u>>v;
        if(find(u)!=find(v)){
            if(!in[find(v)].count(u)){
                in[find(v)].insert(u);
                res+=sz[find(v)];
            }
            bool chk=0;
            for(int j:in[find(u)]){
                if(find(j)==find(v)){
                    chk=1;
                    break;
                }
            }
            if(chk){
                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:91:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
joitter2.cpp:92:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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