Submission #938687

#	Time	Username	Problem	Language	Result	Execution time	Memory
938687		guagua0407	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	100 / 100	1096 ms	89544 KiB

joitter2

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

vector<map<int,int>> S1,S2,R1,R2;
vector<set<int>> belong;
queue<pair<int,int>> q;
ll ans=0;

struct DSU{
    vector<int> e;
    DSU(int n){
        e=vector<int>(n,-1);
        for(int i=0;i<n;i++){
            belong[i].insert(i);
        }
    }
    int find(int x){
        return (e[x]<0?x:e[x]=find(e[x]));
    }
    bool same(int a,int b){
        return find(a)==find(b);
    }
    int sz(int x){
        return -e[find(x)];
    }
    void sir1(int a,int b){
        if(R1[a].size()<sz(b)){
            for(auto it=R1[a].begin();it!=R1[a].end();){
                if(find((*it).f)==b){
                    S1[(*it).f].erase(a);
                    it=R1[a].erase(it);
                }
                else{
                    it++;
                }
            }
        }
        else{
            for(auto v:belong[b]){
                if(R1[a].find(v)!=R1[a].end()){
                    R1[a].erase(v);
                    S1[v].erase(a);
                }
            }
        }
    }
    void sir2(int a,int b){
        if(R2[a].size()<S2[b].size()){
            for(auto v:R2[a]){
                if(S2[b].find(v.f)!=S2[b].end()){
                    q.push({v.f,b});
                }
            }
        }
        else{
            for(auto v:S2[b]){
                if(R2[a].find(v.f)!=R2[a].end()){
                    q.push({v.f,b});
                }
            }
        }
    }
    bool unite(int a,int b){
        a=find(a);
        b=find(b);
        if(a==b) return false;
        ans+=2ll*sz(a)*sz(b)-1ll*S2[a][b]*sz(b)-1ll*S2[b][a]*sz(a);
        //cout<<S2[a][b]<<' '<<sz(b)<<'\n';
        //cout<<S2[b][a]<<' '<<sz(a)<<'\n';
        //cout<<a+1<<' '<<b+1<<' '<<2ll*sz(a)*sz(b)-1ll*S2[a][b]*sz(b)-1ll*S2[b][a]*sz(a)<<'\n';
        // clear (a,b) edges
        S2[a].erase(b);
        S2[b].erase(a);
        R2[a].erase(b);
        R2[b].erase(a);
        sir1(a,b);
        swap(a,b);
        sir1(a,b);
        //new one way edges
        int cnt=0;
        if(R1[a].size()>R1[b].size()) swap(a,b);
        for(auto v:R1[a]){
            if(R1[b].find(v.f)!=R1[b].end()){
                cnt++;
            }
        }
        ans+=1ll*((int)R1[a].size()-cnt)*sz(b)+1ll*((int)R1[b].size()-cnt)*sz(a);
        //out<<a+1<<' '<<b+1<<' '<<1ll*((int)R1[a].size()-cnt)*sz(b)+1ll*((int)R1[b].size()-cnt)*sz(a)<<'\n';
        //new scc edges
        sir2(a,b);
        swap(a,b);
        sir2(a,b);
        // merge
        if(e[a]>e[b]) swap(a,b);
        for(auto v:R1[b]){
            if(R1[a].find(v.f)!=R1[a].end()){
                S2[find(v.f)][a]--;
                if(S2[find(v.f)][a]==0) S2[find(v.f)].erase(a);
                R2[a][find(v.f)]--;
                if(R2[a][find(v.f)]==0) R2[a].erase(find(v.f));
            }
        }
        for(auto v:S2[b]){
            S2[a][v.f]+=v.s;
            R2[v.f].erase(b);
            R2[v.f][a]+=v.s;
        }
        for(auto v:R1[b]){
            S1[v.f].erase(b);
            S1[v.f][a]=1;
            R1[a][v.f]=1;
        }
        for(auto v:R2[b]){
            S2[v.f].erase(b);
            S2[v.f][a]+=v.s;
            R2[a][v.f]+=v.s;

        }
        e[a]+=e[b];
        e[b]=a;
        for(auto v:belong[b]){
            belong[a].insert(v);
        }
        return true;
    }
};

int main() {_
    int n,m;
    cin>>n>>m;
    //assert(n==4 and m==6);
    S1.resize(n);
    S2.resize(n);
    R1.resize(n);
    R2.resize(n);
    belong.resize(n);
    DSU dsu(n);
    for(int i=0;i<m;i++){
        int a,b;
        cin>>a>>b;
        a--;
        b--;
        if(dsu.same(a,b)){
            cout<<ans<<'\n';
            continue;
        }
        int pa=dsu.find(a);
        int pb=dsu.find(b);
        if(S1[a].find(pb)!=S1[a].end()){
            cout<<ans<<'\n';
            continue;
        }
        S1[a][pb]++;
        S2[pa][pb]++;
        R1[pb][a]=1;
        R2[pb][pa]++;
        ans+=dsu.sz(pb);
        //cout<<"-"<<'\n';
        if(S2[pb].find(pa)!=S2[pb].end()){
            //cout<<i+1<<' '<<pa+1<<' '<<pb+1<<'\n';
            q.push({pa,pb});
            while(!q.empty()){
                auto tmp=q.front();
                q.pop();
                dsu.unite(tmp.f,tmp.s);
            }
        }
        cout<<ans<<'\n';
    }
    return 0;
}
//maybe its multiset not set
//yeeorz
//laborz

Compilation message (stderr)

joitter2.cpp: In member function 'void DSU::sir1(int, int)':
joitter2.cpp:42:24: warning: comparison of integer expressions of different signedness: 'std::map<int, int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   42 |         if(R1[a].size()<sz(b)){
      |            ~~~~~~~~~~~~^~~~~~
joitter2.cpp: In function 'void setIO(std::string)':
joitter2.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
joitter2.cpp:16:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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