Submission #958356

#	Time	Username	Problem	Language	Result	Execution time	Memory
958356		MisterReaper	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	100 / 100	901 ms	70736 KiB

joitter2

#include <bits/stdc++.h>
using i64 = long long;

constexpr int maxN = 1E5 + 5;

std::set<int> in[maxN], rev[maxN], graph[maxN];
std::queue<std::pair<int, int>> strong;
i64 ans = 0;
int par[maxN], sz[maxN];

int find(int a) {
    if(par[a] == a) {
        return a;
    }
    return par[a] = find(par[a]);
}

void connect(int a, int b) {
    graph[a].emplace(b);
    rev[b].emplace(a);
    if(graph[b].count(a)) {
        strong.emplace(a, b);
    }
}

void unite(int a, int b) {
    a = find(a), b = find(b);
    if(a == b) {
        return;
    }

    if(sz[a] < sz[b]) {
        std::swap(a, b);
    }

    ans += 1LL * in[b].size() * sz[a] + 1LL * in[a].size() * sz[b];

    sz[a] += sz[b];
    par[b] = a;

    for(int v : in[b]) {
        if(!in[a].count(v)) {
            in[a].emplace(v);
        } else {
            ans -= sz[a];
        }
    }

    graph[a].erase(b);
    graph[b].erase(a);
    rev[a].erase(b);
    rev[b].erase(a);
    for(int v : graph[b]) {
        rev[v].erase(b);
        connect(a, v);
    }
    for(int v : rev[b]) {
        graph[v].erase(b);
        connect(v, a);
    }
}

void solve() {
    int n, m;
    std::cin >> n >> m;

    for(int _ = 1; _ <= m; _++) {
        int a, b;
        std::cin >> a >> b;

        if(find(a) != find(b) && !in[find(b)].count(a)) {
            in[find(b)].emplace(a);
            ans += sz[find(b)];
            connect(find(a), find(b));
            while(!strong.empty()) {
                auto [u, v] = strong.front();
                strong.pop();
                unite(u, v);
            }
        }

        std::cout << ans << "\n";
    }
    
    return;
}

signed main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    std::iota(par, par + maxN, 0);
    std::fill(sz, sz + maxN, 1);
    for(int i = 0; i < maxN; i++) {
        in[i].emplace(i);
    }

    int t = 1; //std::cin >> t;
    for(int i = 1; i <= t; i++) {
        solve();
    }

    return 0;
}

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