Submission #1170846

#	Time	Username	Problem	Language	Result	Execution time	Memory
1170846		SmuggingSpun	Making Friends on Joitter is Fun (JOI20_joitter2)	C++20	0 / 100	0 ms	396 KiB

joitter2

#include<bits/stdc++.h>
#define taskname "B"
using namespace std;
typedef long long ll;
int n, m;
namespace sub1{
    void solve(){
        vector<ll>g(n, 0), _g;
        for(int _ = 0; _ < m; _++){
            int u, v;
            cin >> u >> v;
            g[--u] |= 1LL << --v;
            _g = g;
            while(true){
                bool flag = false;
                for(int i = 0; i < n; i++){
                    for(int j = 0; j < n; j++){
                        if(1LL << j & _g[i]){
                            for(int k = 0; k < n; k++){
                                if(k != i && k != j && (1LL << j & _g[k]) && (1LL << k & _g[j]) && ((_g[i] >> ll(k) & 1LL) == 0)){
                                    _g[i] |= 1LL << k;
                                    flag = true;
                                }
                            }
                        }
                    }
                }
                if(!flag){
                    break;
                }
            }
            int ans = 0;
            for(int i = 0; i < n; i++){
                ans += __builtin_popcountll(_g[i]);
            }
            cout << ans << "\n";
        }
    }
}
namespace sub2{
    const int lim = 2e3 + 1;
    void solve(){
        vector<int>parent(n + 1);
        vector<vector<int>>vertex(n + 1);
        vector<bitset<lim>>g(n + 1), in(n + 1);
        for(int i = 1; i <= n; i++){
            g[i].reset();
            in[i].reset();
        }
        int cnt = 0;
        auto find_set = [&] (int N){
            while(N != parent[N]){
                N = parent[N] = parent[parent[N]];
            }
            return N;
        };
        auto merge = [&] (int u, int v){
            u = find_set(u);
            v = find_set(v);
            for(int i = 1; i <= n; i++){
                if(in[u].test(i) && u != find_set(i)){
                    cnt -= vertex[u].size();
                }
                if(in[v].test(i) && v != find_set(i)){
                    cnt -= vertex[v].size();
                }
            }
            in[parent[v] = u] |= in[v];
            for(int& j : vertex[v]){
                vertex[u].emplace_back(j);
            }
            for(int i = 1; i <= n; i++){
                if(in[u].test(i) && u != find_set(i)){
                    cnt += vertex[u].size();
                }
            }
        };
        for(int i = 1; i <= n; i++){
            vertex[i].emplace_back(parent[i] = i);
        }
        for(int _ = 0; _ < m; _++){
            int u, v;
            cin >> u >> v;
            if(find_set(u) != find_set(v) && !in[find_set(v)].test(u)){
                g[u].set(v);
                cnt += vertex[find_set(v)].size();
                in[find_set(v)].set(u);
                bool flag = false;
                for(int i = 1; i <= n; i++){
                    if((find_set(i) == find_set(v) && g[i].test(u)) || (i == find_set(u) && g[v].test(i))){
                        flag = true;
                        break;
                    }
                }
                if(flag){
                    merge(u, v);
                }
            }
            int ans = cnt;
            for(int i = 1; i <= n; i++){
                if(i == find_set(i)){
                    ans += vertex[i].size() * (int(vertex[i].size()) - 1);
                }
            }
            cout << ans << "\n";
        }
    }
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	if(fopen(taskname".inp", "r")){
		freopen(taskname".inp", "r", stdin);
	}
    cin >> n >> m;
    if(n <= 50){
        sub2::solve();
    }
    else if(n <= 2000){
        sub2::solve();
    }
}

Compilation message (stderr)

joitter2.cpp: In function 'int main()':
joitter2.cpp:112:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  112 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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