Submission #626048

#	Time	Username	Problem	Language	Result	Execution time	Memory
626048		Soul234	Making Friends on Joitter is Fun (JOI20_joitter2)	C++14	17 / 100	105 ms	39252 KiB

joitter2

#include<bits/stdc++.h>
using namespace std;

void DBG() { cerr << "]\n"; }
template<class H, class... T> void DBG(H h, T... t) {
    cerr << h; if(sizeof...(t)) cerr << ", ";
    DBG(t...);
}
#ifdef LOCAL
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 0
#endif // LOCAL

#define FOR(i,a,b) for(int i = (a) ; i<(b) ; i++)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for(int i = (b)-1 ; i>=(a) ; i--)
#define R0F(i,a) ROF(i,0,a)
#define each(e,a) for(auto &e : (a))
#define sz(v) (int)(v).size()
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define pb push_back
#define tcT template<class T
#define nl "\n"
#define fi first
#define se second
#define ins insert

using ll = long long;
using vi = vector<int>;
using pi = pair<int,int>;
using str = string;
tcT> using V = vector<T>;
tcT> using pqg = priority_queue<T,vector<T>,greater<T>>;

void setIO(string NAME = "") {
    cin.tie(0)->sync_with_stdio(0);
    if(sz(NAME)) {
        freopen((NAME + ".inp").c_str(),"r",stdin);
        freopen((NAME + ".out").c_str(),"w",stdout);
    }
}

tcT> bool ckmin(T&a, const T&b) {
    return b < a ? a=b,1 : 0; }
tcT> bool ckmax(T&a, const T&b) {
    return b > a ? a=b,1 : 0; }

const int MOD = 1e9 + 7;
const int MX = 1e5+5;

struct UF {
    int N; vi e;
    queue<pi> q;
    set<int> adj[MX], radj[MX], fl_ers[MX];
    ll curans = 0;
    void init(int _N) {
        N = _N;
        e.assign(N + 1, -1);
        FOR(i, 1, N+1) {
            fl_ers[i].ins(i);
        }
    }
    int find(int x) { return e[x] < 0 ? x : e[x] = find(e[x]); }

    int get_size(int x) { return sz(adj[x]) + sz(radj[x]) + sz(fl_ers[x]); }

    void insFollow(int a, int b) {
        adj[a].ins(b);
        radj[b].ins(a);
        if(adj[b].count(a)) q.push({a, b});
    }

    void join(int a, int b) {
        if(a == b) return;

        if(get_size(a) < get_size(b)) swap(a, b);

        curans += -1LL*e[a]*sz(fl_ers[b]) - 1LL*e[b]*sz(fl_ers[a]);

        e[a] += e[b];
        e[b] = a;

        each(v, fl_ers[b]) {
            if(fl_ers[a].count(v)) curans += e[a];
            else fl_ers[a].ins(v);
        }

        assert(adj[a].count(b) && adj[b].count(a));
        assert(radj[a].count(b) && radj[b].count(a));

        adj[a].erase(b); radj[a].erase(b);
        adj[b].erase(a); radj[b].erase(a);

        each(v, adj[b]) {
            assert(radj[v].count(b));
            radj[v].erase(b);
            insFollow(a, v);
        }

        each(v, radj[b]) {
            assert(adj[v].count(b));
            adj[v].erase(b);
            insFollow(v, a);
        }
    }

    void query_upd(int a, int b) {
        b = find(b);
        if(find(a) == b || fl_ers[b].count(a)) return;
        fl_ers[b].ins(a);
        curans -= e[b];

        a = find(a);
        insFollow(a, b);

        while(!q.empty()) {
            tie(a, b) = q.front();
            q.pop();
            join(find(a), find(b));
        }
    }
};

int N, M;
UF dsu;

void solve() {
    cin >> N >> M;
    dsu.init(N+5);
    while(M-- > 0) {
        int a, b;
        cin >> a >> b;
        dsu.query_upd(a, b);
        cout << dsu.curans << nl;
    }
}

int main() {
    setIO();

    int t=1;
    //cin>>t;
    while(t-->0) {
        solve();
    }

    return 0;
}

Compilation message (stderr)

joitter2.cpp: In function 'void setIO(std::string)':
joitter2.cpp:40:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |         freopen((NAME + ".inp").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
joitter2.cpp:41:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |         freopen((NAME + ".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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