제출 #42366

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
42366		nickyrio	우호 조약 체결 (JOI14_friends)	C++14	0 / 100	100 ms	27188 KiB

friends

#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = a; i<= b; ++i)
#define FORD(i, a, b) for (int i = a; i>=b; --i)
#define REP(i, a) for (int i = 0; i<a; ++i)
#define DEBUG(x) { cerr << #x << " = " << x << endl; }
#define Arr(A, l, r) { cerr << #A  << " = "; FOR(_, l, r) cerr << A[_] << ' '; cerr << endl; }
#define N 1001000
#define pp pair<int, int>
#define next __next
#define prev __prev
#define __builtin_popcount __builtin_popcountll
#define bit(S, i) (((S) >> i) & 1)
#define IO ios::sync_with_stdio(false); cin.tie(NULL);cout.tie(NULL);

using namespace std;

int n, m, f[N];
vector<int> e[N];

void Union(int a, int b) {
    int t = f[a] + f[b];
    if (f[a] > f[b]) swap(a, b);
    f[a] = t;
    f[b] = a;
}

int root(int u) { return f[u] < 0 ? u : (f[u] = root(f[u])); }

int main() {
    IO;
    cin >> n >> m;
    REP(i, m) {
        int u, v;
        cin >> u >> v;
        e[u].push_back(v);
    }
    FOR(i, 1, n) f[i] = -1;
    FOR(u, 1, n) {
        int r = -1;
        for (int v : e[u]) {
            if (r == -1) r = v;
            else {
                int a = root(r);
                int b = root(v);
                if (a != b) Union(a, b);
            }
        }
    }
    long long ans = 0;
    FOR(u, 1, n) {
        for (int v : e[u]) if (root(u) != root(v)) ans++;
        if (f[u] < 0) ans += 1ll * f[u] * (f[u] + 1);
    }
    cout << ans;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 30
• Subtask 3: 0 / 65