Submission #1020624

#	Time	Username	Problem	Language	Result	Execution time	Memory
1020624		khanhphucscratch	Making Friends on Joitter is Fun (JOI20_joitter2)	C++14	0 / 100	13 ms	15960 KiB

joitter2

#include<bits/stdc++.h>
#define int long long
using namespace std;
multiset<pair<int, bool>> ad[100005];
unordered_set<int> sus[100005], node[100005];
int ans = 0, root[100005], sz[100005], deg[100005];
int getroot(int u)
{
    if(root[u] == u) return u;
    else return getroot(root[u]);
}
void unite(int u, int v)
{
    u = getroot(u); v = getroot(v);
    if(u == v) return;
    root[v] = u; sz[u] += sz[v];
}
set<int> mergeComponent(int u, int v)
{
    u = getroot(u); v = getroot(v);
    if(u == v) return {};
    if(sz[u] < sz[v]) swap(u, v);
    //Erase all edges between two components
    int num = ad[v].count({u, 0}), num2 = ad[u].count({v, 0});
    set<int> add;
    ans += -num*sz[u] - num2*sz[v]+ 2*sz[u]*sz[v];
    deg[u] -= num; deg[v] -= num2;
    ad[v].erase({u, 0}); ad[v].erase({u, 1});
    ad[u].erase({v, 0}); ad[u].erase({v, 1});
    //Merge ad[] vector
    for(pair<int, bool> i : ad[v]){ //Merge to ad[u]
        if(ad[i.first].count(make_pair(u, i.second)) > 0) add.insert(i.first);/**/
        ad[u].insert(i);
        pair<int, bool> j = make_pair(v, i.second^1);
        ad[i.first].erase(j);
        j.first = u;
        ad[i.first].insert(j);
    }
    //Merge sus[]
    for(int i : sus[v]){
        if(node[u].count(i) == 0) sus[u].insert(i);
    }
    for(int i : node[v]){
        node[u].insert(i);
        if(sus[u].count(i) == 1) sus[u].erase(i);
    }
    ans += -deg[u]*sz[u] - deg[v]*sz[v] + sus[u].size()*(sz[u]+sz[v]);
    deg[u] += deg[v]; deg[v] = 0;
    unite(u, v);
    /*cout<<"A"<<sus[u].size()<<" "<<u<<" "<<v<<endl;
    for(int i : sus[u]) cout<<i<<" ";
    cout<<endl;*/
    return add;
}
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin>>n>>m;
    for(int i = 1; i <= n; i++){
        root[i] = i; sz[i] = 1; node[i].insert(i);
    }
    for(int test = 1; test <= m; test++){
        int u, v;
        cin>>u>>v;
        int reu = u;
        u = getroot(u); v = getroot(v);
        if(u == v || sus[v].count(reu) == 1){cout<<ans<<'\n'; continue;}
        int num = ad[v].count({u, 0});
        if(num > 0){
            //Merge two components
            vector<int> order; order.push_back(v);
            for(int i = 0; i < order.size(); i++){
                set<int> x = mergeComponent(u, order[i]);
                for(int j : x) order.push_back(j);
            }
        }
        else{
            ans += sz[v];
            ad[u].insert({v, 0});
            ad[v].insert({u, 1});
            sus[v].insert(reu);
            deg[v]++;
        }
        cout<<ans<<'\n';
    }
}

Compilation message (stderr)

joitter2.cpp: In function 'int main()':
joitter2.cpp:74:30: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |             for(int i = 0; i < order.size(); i++){
      |                            ~~^~~~~~~~~~~~~~

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