Submission #1108560

#	Time	Username	Problem	Language	Result	Execution time	Memory
1108560		sitablechair	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	0 / 100	3 ms	15160 KiB

joitter2

#include <bits/stdc++.h>

#define ll long long
#define ldb long double
#define endl '\n'
#define For(i,l,r) for(int i=l;i<=r;i++)
#define ForD(i,r,l) for(int i=r;i>=l;i--)
#define REP(i,l,r) For(i,l,r-1)
#define PER(i,r,l) ForD(i,r-1,l)
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define All(x,n) x+1,x+1+n
#define Alll(x,n) x,x+n
#define sz(x) (signed)x.size()
#define unq(x) x.resize(unique(all(x))-x.begin())
#define mpa make_pair

#ifdef NCGM
#include"debug.h"
#else 
#define debug(...) "fr";
#endif

using namespace std;
 
const int N=1e5+3;
 
int n,m,f[N],f1[N],mmb[N];
ll ans=0;
map<int,int> mp[N],mp1[N];
set<int> st[N];
vector<int> ahu,ahu1;
int find_set(int u) {
    return (f[u]<0?u:f[u]=find_set(f[u]));
}
int find_set1(int u) {
    return (f1[u]<0?u:f1[u]=find_set1(f1[u]));
}
 
 
void unite(int u,int v) {
    int a=find_set(u),b=find_set(v);
    if (a==b) return;
    int a1=find_set1(u),b1=find_set1(v);
    ans+=1LL*f[a]*(sz(st[a1])-1);
    ans+=1LL*f[b]*(sz(st[b1])-1);
    if (sz(st[a1])<sz(st[b1])) swap(a1,b1);
    if (sz(mp[a])+sz(mp1[a])<sz(mp[b])+sz(mp1[b])) swap(a,b);
    ahu.clear();
    ahu1.clear();
    for(auto el: mp[b]) {
        ahu.pb(el.ff);
        if (mp[find_set(el.ff)].count(a) || mp[find_set(el.ff)].count(b)) ahu1.pb(el.ff);
    }
    for(auto el: mp1[b])
        if (mp1[el.ff].count(a) || mp1[el.ff].count(b)) ahu1.pb(el.ff);
 
    for(auto el: mp1[b1]) {
        mp[el.ff][a]=mp[el.ff][b];
        mp[el.ff].erase(mp[el.ff].find(b));
    }
    for(auto el: ahu) {
        mp1[el][a]=mp1[el][b];
        mp1[el].erase(mp1[el].find(b));
    }
    for(auto el: st[b1]) st[a1].insert(b1);
    st[b1].clear();
    for(auto el: mp[b]) mp[a][el.ff]+=el.ss;
    mp[b].clear();
    for(auto el: mp1[b]) mp1[a][el.ff]+=el.ss;
    mp1[b].clear();
    //if (u==1 && v==2) debug(mmb[a],find_set1(3));
    f[a]+=f[b];
    f1[a1]+=f1[b1];
    f[b]=a;
    f1[b1]=a1;
    ans-=1LL*f[a]*(sz(st[find_set1(a)])-1);
    for(auto el: ahu1) {
        if (find_set(el)==find_set(a)) continue;
        unite(el,a);
    }
}
void add_edge(int u,int v) {
    if (find_set(u)==find_set(v) || mp[find_set(v)].count(find_set(u))) return;
    ans-=f[find_set(v)];
    mp[find_set(v)][find_set(u)]++;
    mp1[find_set(u)][find_set(v)]++;
    st[find_set1(v)].insert(u);
    if (mp[find_set(u)].count(find_set(v))) unite(u,v);
}
int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> m;
    For(i,1,n) f[i]=f1[i]=-1;
    For(i,1,n) st[i].insert(i);
    For(i,1,m) {
        int u,v;
        cin >> u >> v;
        add_edge(u,v);
        cout << ans << endl;
    }
    return 0;
}

Compilation message (stderr)

joitter2.cpp: In function 'void unite(int, int)':
joitter2.cpp:68:14: warning: unused variable 'el' [-Wunused-variable]
   68 |     for(auto el: st[b1]) st[a1].insert(b1);
      |              ^~

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