Submission #1124538

#	Time	Username	Problem	Language	Result	Execution time	Memory
1124538		Whisper	Making Friends on Joitter is Fun (JOI20_joitter2)	C++20	100 / 100	801 ms	66140 KiB

joitter2

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define int long long
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (b); i >= (a); i --)
#define REP(i, a) for (int i = 0; i < (a); ++i)
#define REPD(i, a) for (int i = (a) - 1; i >= 0; --i)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)


constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

/*
    Phu Trong from Nguyen Tat Thanh High School for gifted student
*/

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
#define MAX                         100005
//M log (M)^2
int pa[MAX], siz[MAX];
int ans = 0;

int numNode, numEdge;

int fp(int u){
    return pa[u] == u ? u : pa[u] = fp(pa[u]);
}
set<int> adj[MAX], radj[MAX], child[MAX];
queue<pair<int, int>> todo;

void add_weak_edge(int u, int v){
    adj[u].insert(v);
    radj[v].insert(u);

    if(adj[v].count(u)){
        //a strong edge appears
        todo.emplace(u, v);
    }
}

int getSize(int u){
    return (int)adj[u].size() + (int)radj[u].size() + (int)child[u].size();
}

void joint(int u, int v){
    u = fp(u), v = fp(v);
    if(u == v) return;

    if(getSize(u) < getSize(v)) swap(u, v);
    ans += 1LL * siz[u] * (int)child[v].size() + 1LL * siz[v] * (int)child[u].size();

    pa[v] = u; siz[u] += siz[v];

    for (auto&s : child[v]){
        if(child[u].count(s)) ans -= siz[u];
        else child[u].insert(s);
    }

    adj[u].erase(v); radj[u].erase(v);
    adj[v].erase(u); radj[v].erase(u);

    for (int i : adj[v]){
        radj[i].erase(v);
        add_weak_edge(u, i);
    }
    for (int i : radj[v]){
        adj[i].erase(v);
        add_weak_edge(i, u);
    }
}


void process(void){
    cin >> numNode >> numEdge;
    for (int i = 1; i <= numNode; ++i){
        siz[i] = 1;
        child[i].insert(i);
        pa[i] = i;
    }

    for (int i = 1; i <= numEdge; ++i){
        int u, v; cin >> u >> v;
        v = fp(v);
        if(!child[v].count(u) and fp(u) != v){
            child[v].insert(u); //u is v's child if u is following v
            ans += siz[v];

            u = fp(u);

            add_weak_edge(u, v);

            while(todo.size()){
                int u, v; tie(u, v) = todo.front(); todo.pop();
                joint(u, v);
            }
        }
        cout << ans << '\n';
    }
}
signed main(){
    #define name "Whisper"
    cin.tie(nullptr) -> sync_with_stdio(false);
    // freopen(name".inp", "r", stdin);
    // freopen(name".out", "w", stdout);
    process();
    return (0 ^ 0);
}

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