Submission #833611

#	Time	Username	Problem	Language	Result	Execution time	Memory
833611		maomao90	Making Friends on Joitter is Fun (JOI20_joitter2)	C++17	0 / 100	20 ms	42604 KiB

joitter2

// Hallelujah, praise the one who set me free
// Hallelujah, death has lost its grip on me
// You have broken every chain, There's salvation in your name
// Jesus Christ, my living hope
#include <bits/stdc++.h> 
using namespace std;

#define REP(i, s, e) for (int i = (s); i < (e); i++)
#define RREP(i, s, e) for (int i = (s); i >= (e); i--)
template <class T>
inline bool mnto(T& a, T b) {return a > b ? a = b, 1 : 0;}
template <class T>
inline bool mxto(T& a, T b) {return a < b ? a = b, 1: 0;}

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
#define FI first
#define SE second
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
#define ALL(_a) _a.begin(), _a.end()
#define SZ(_a) (int) _a.size()
#define pb push_back
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<ii> vii;
typedef vector<iii> viii;

#ifndef DEBUG
#define cerr if (0) cerr
#endif

const int INF = 1000000005;
const ll LINF = 1000000000000000005ll;
const int MAXN = 300005;

int n, m;
ll ans;

struct thing {
    int v, u;
    bool operator< (const thing &o) const {
        return v < o.v;
    }
};

set<thing> adj[MAXN];
set<ii> iadj[MAXN];
set<int> adjp[MAXN];
int p[MAXN], sz[MAXN];
void init() {
    REP (i, 1, n + 1) {
        p[i] = i;
        sz[i] = 1;
    }
}
int findp(int i) {
    if (p[i] == i) {
        return i;
    }
    return p[i] = findp(p[i]);
}
bool join(int a, int b) {
    int pa = findp(a), pb = findp(b);
    if (pa == pb) {
        return 1;
    }
    if (sz[pa] < sz[pb]) {
        swap(pa, pb);
    }
    ans -= (ll) SZ(adj[pa]) * sz[pa];
    ans -= (ll) SZ(adj[pb]) * sz[pb];
    adjp[pa].erase(pb);
    adjp[pb].erase(pa);
    for (auto [v, u] : adj[pb]) {
        if (findp(v) == pa) {
            iadj[pa].erase({u, v});
        } else {
            adj[pa].insert({v, u});
            adjp[pa].insert(findp(v));
        }
    }
    for (int v : adjp[pb]) {
        adjp[pa].insert(v);
    }
    for (auto [a, b] : iadj[pb]) {
        if (findp(a) == pa) {
            adj[pa].erase({b, a});
        } else {
            iadj[pa].insert({a, b});
            adjp[findp(a)].erase(pb);
            adjp[findp(a)].insert(pa);
        }
    }
    /*
    for (auto [x, y] : eg[pa][pb]) {
        adj[pa].erase(y);
    }
    for (auto [x, y] : eg[pb][pa]) {
        adj[pb].erase(y);
    }
    */
    ans -= (ll) sz[pa] * (sz[pa] - 1);
    ans -= (ll) sz[pb] * (sz[pb] - 1);
    sz[pa] += sz[pb];
    ans += (ll) sz[pa] * (sz[pa] - 1);
    ans += (ll) SZ(adj[pa]) * sz[pa];
    p[pb] = pa;
    return 1;
}

int main() {
#ifndef DEBUG
    ios::sync_with_stdio(0), cin.tie(0);
#endif
    cin >> n >> m;
    init();
    REP (i, 0, m) {
        int a, b; cin >> a >> b;
        if (findp(a) != findp(b)) {
            bool gd = adj[findp(b)].insert({a, b}).SE;
            if (gd) {
                ans += sz[findp(b)];
            }
            iadj[findp(a)].insert({b, a});
            adjp[findp(b)].insert(findp(a));
            if (adjp[findp(a)].count(findp(b))) {
                cerr << "JOIN " << a << ' ' << b << '\n';
                join(a, b);
            }
        }
        /*
        while (1) {
            bool fnd = 0;
            RREP (j, i, 0) {
                RREP (k, j - 1, 0) {
                    if (findp(a[j]) == findp(b[k]) && findp(a[k]) == findp(b[j]) && findp(a[j]) != findp(b[j])) {
                        fnd = 1;
                        join(a[j], b[j]);
                    }
                }
            }
            if (!fnd) {
                break;
            }
        }
        ll ans = 0;
        set<ii> st;
        RREP (j, i, 0) {
            if (findp(a[j]) == findp(b[j])) {
                continue;
            }
            int pa = a[j], pb = findp(b[j]);
            if (st.find({pa, pb}) != st.end()) {
                continue;
            }
            st.insert({pa, pb});
            ans += sz[pb];
        }
        REP (j, 1, n + 1) {
            if (findp(j) != j) {
                continue;
            }
            ans += (ll) sz[j] * (sz[j] - 1);
        }
        cout << ans << '\n';
        */
        cout << ans << '\n';
    }
    return 0;
}

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