Submission #213207

#	Time	Username	Problem	Language	Result	Execution time	Memory
213207		_7_7_	Making Friends on Joitter is Fun (JOI20_joitter2)	C++14	0 / 100	14 ms	16768 KiB

joitter2

#include <bits/stdc++.h>                                           
 
//#define int long long
//#pragma GCC optimize("Ofast")
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4")
 
 
#define file(s) freopen(s".in","r",stdin); freopen(s".out","w",stdout);
#define all(x) x.begin(), x.end()
#define sz(s) (int)s.size()
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define s second
#define f first
 
 
using namespace std;
 
 
typedef pair < long long, long long > pll;    
typedef pair < int, int > pii;
typedef unsigned long long ull;         
typedef vector < pii > vpii;
typedef vector < int > vi;
typedef long double ldb;  
typedef long long ll;  
typedef double db;                             
 
 
const int dx[] = {1, -1, 0, 0}, dy[] = {0, 0, 1, -1}, block = 333;
const pii base = mp(1171, 3307), Mod = mp(1e9 + 7, 1e9 + 9);
const int inf = 1e9, maxn = 4e5 + 148, mod = 1e9 + 7, N = 3e5 + 11;
const db eps = 1e-12, pi = 3.14159265359;
const ll INF = 1e18;


int n, m, v, u, p[N], cnt[N];
unordered_set < int > g[N];
ll ans;

int get (int v) {
	return v == p[v] ? v : p[v] = get(p[v]);
}

void merge (int v, int u) {
	if (sz(g[v]) < sz(g[u]))
		swap(v, u);

/*	for (auto x : g[v])
		cerr << x << ' ';
	cerr << endl;
	for (auto x : g[u])
		cerr << x << ' ';
	cerr << endl << endl;*/

	int common = 0;
	for (auto x : g[u]) 
		if (g[v].count(x)) 
			++common;

//	cerr << common << endl;
	ans += (sz(g[u]) - common) * 1ll * cnt[v];
	ans += (sz(g[v]) - common) * 1ll * cnt[u];



	p[u] = v;
	cnt[v] += cnt[u];

	for (auto x : g[u])
		g[v].insert(x);
}

main () {
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; ++i) {
		p[i] = i;
		cnt[i] = 1;
		g[i].insert(i);
	}

	while (m--) {
		scanf("%d%d", &u, &v);
		int V = get(v), U = get(u);
		if (!g[V].count(u)) {
			if (g[U].count(v))
				merge(V, U);
			else {
				ans += cnt[V];
				g[V].insert(u);
			}
		}
		printf("%lld\n", ans);
	}
}

Compilation message (stderr)

joitter2.cpp:76:7: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main () {
       ^
joitter2.cpp: In function 'int main()':
joitter2.cpp:77:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~
joitter2.cpp:85:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &u, &v);
   ~~~~~^~~~~~~~~~~~~~~~

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