Submission #797150

#	Time	Username	Problem	Language	Result	Execution time	Memory
797150		vjudge1	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	0 / 100	3 ms	5716 KiB

joitter2

#include<bits/stdc++.h>

using namespace std;
using ll = long long;

const int N = 100100;

struct MEGA_DSU {

    map<pair<int, int>, int> w;
    set<int> children[N];
    vector<int> p, sz;

    void init() {
        p.resize(N);
        iota(p.begin(), p.end(), 0);
        sz.resize(N, 1);
    }
    int get(int v) {
        return p[v] = (p[v] == v ? v : get(p[v]));
    }
    void merge(int u, int v) {
        u = get(u);
        v = get(v);
        if(u == v) return;
        if(sz[u] < sz[v]) swap(u, v);
        p[v] = u;
        sz[u] += sz[v];
    }
    ll ans;

    void combine(int u, int v) {
        u = get(u), v = get(v);
        if(u == v) return;
        // cout << u << ' ' << v << '\n';
        // cout << sz[u] << ' ' << sz[v] << ' ' << w[make_pair(u, v)] << ' ' << w[make_pair(v, u)] << '\n';
        ans += 2ll * sz[u] * sz[v] - 1ll * w[make_pair(u, v)] * sz[v] - 1ll * w[make_pair(v, u)] * sz[u];
        w[make_pair(u, v)] = sz[u];
        w[make_pair(v, u)] = sz[v];
        if(p[u] != u) swap(u, v);

        for(int child : children[v]) 
            add_edge(child, u);
        for(int child : children[u]) 
            add_edge(child, v);
        merge(u, v);
        if(children[u].empty()) return;
        set<int> st;
        for(int child : children[u]) {
            if(get(child) == u) continue;
            st.insert(child);
        }
        children[u] = st;
    }

    void add_edge(int u, int v) {
        u = get(u), v = get(v);
        if(u == v) return;
        if(w.count(make_pair(u, v))) return;
        if(w.count(make_pair(v, u))) return void(combine(v, u));
        ans += sz[v];
        w[make_pair(u, v)]++;
        if(w[make_pair(u, v)] == 1) children[v].insert(u);
    }
};

MEGA_DSU d;
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    int n, m;
    cin >> n >> m;
    d.init();
    for(int i = 1; i <= m; i++) {
        int u, v;
        cin >> u >> v;
        d.add_edge(u, v);
        cout << d.ans << '\n';
    }
}

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