Submission #1199589

#	Time	Username	Problem	Language	Result	Execution time	Memory
1199589		hoa208	Making Friends on Joitter is Fun (JOI20_joitter2)	C++20	100 / 100	497 ms	65068 KiB

joitter2

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; i++)
#define FORD(i, b, a) for (int i = (b), _a = (a); i >= _a; i--)
#define pa pair<ll, ll>
#define fi first
#define se second
#define bit(mask, j) ((mask >> j) & 1)
#define t_test int t;cin >> t;while(t--)
const   ll mod = 1e9 + 7;
const   ll INF = 1e18;
inline  void adm(ll &x){if(x>=mod)x%=mod;else if(x<0)x+=mod;}
//--------------------------------------------------------------------
const ll N = 1e5 + 10;
const ll M = 3e5 + 10;
ll n, m;
ll ans = 0;
set<ll> child[N], indeg[N], outdeg[N];
ll p[N], sz[N];
queue<pa> q;
ll findset(ll u)
{
    return u == p[u] ? u : p[u] = findset(p[u]);
}
ll size_dsu(ll &u) {
    return child[u].size() + indeg[u].size() + outdeg[u].size();
}
void ghep(ll u, ll v)
{
    u = findset(u);
    v = findset(v);
    if(u == v) return;
    if(size_dsu(u) < size_dsu(v)) swap(u, v);
    ans += sz[u] * child[v].size() + sz[v] * child[u].size();
    sz[u] += sz[v];
    p[v] = u;
    for(auto e : child[v]) {
        if(child[u].count(e)) ans -= sz[u];
        else child[u].insert(e);
    }
    child[v].clear();
    indeg[u].erase(v), outdeg[u].erase(v);
	indeg[v].erase(u), outdeg[v].erase(u);
    for(auto e : indeg[v]) {
        outdeg[e].erase(v);
        indeg[u].insert(e);
        outdeg[e].insert(u);
        if(outdeg[u].count(e)) {
            q.push({e, u});
        }
    }
    for(auto e : outdeg[v]) {
        indeg[e].erase(v);
        outdeg[u].insert(e);
        indeg[e].insert(u);
        if(indeg[u].count(e)) {
            q.push({e, u});
        }
    }
}
void hbmt() {
    cin >> n >> m;
    FOR(i, 1, n) {
        p[i] = i;
        sz[i] = 1;
        child[i].insert(i);
    }
    FOR(i, 1, m) {
        ll u, v;
        cin >> u >> v;
        ll _u = findset(u), _v = findset(v);
        if(!child[_v].count(u)) {
            ans += sz[_v];
            indeg[_v].insert(_u);
            outdeg[_u].insert(_v);
            child[_v].insert(u);
            if(outdeg[_v].count(_u)) q.push({_u, _v});
            while(!q.empty()) {
                pa v = q.front();
                q.pop();
                ghep(v.fi, v.se);
            }
        }
        cout << ans << '\n';
    }
}

int main() {
    
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    
    if(fopen("hbmt.inp", "r")) {
        freopen("hbmt.inp", "r", stdin);
        freopen("hbmt.out", "w", stdout);
    }
    
    // t_test 
    hbmt();
    return 0;
}

Compilation message (stderr)

joitter2.cpp: In function 'int main()':
joitter2.cpp:95:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   95 |         freopen("hbmt.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
joitter2.cpp:96:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   96 |         freopen("hbmt.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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