Submission #259669

#	Time	Username	Problem	Language	Result	Execution time	Memory
259669		_7_7_	Duathlon (APIO18_duathlon)	C++14	0 / 100	271 ms	49144 KiB

count_triplets

#include <bits/stdc++.h>                                           
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
//#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 fastio ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
#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
 
 
 
 
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;
 
typedef tree < int, null_type, less < int >, rb_tree_tag, tree_order_statistics_node_update > ordered_set;
 
const int inf = 1e9, maxn = 2e5 + 48, mod = 998244353, N = 1e5 + 12;
const int dx[] = {1, -1, 0, 0}, dy[] = {0, 0, 1, -1}, block = 300;
const pii base = mp(1171, 3307), Mod = mp(1e9 + 7, 1e9 + 9);
const db eps = 1e-12, pi = acos(-1);
const ll INF = 1e18;
 

int n, m, v, u, k, col[N], cnt[N], K, Sz[N], par[N], cnt1[N];
int tin[N], fup[N], timer, col1[N], kk, Cnt[N], col2[N];
unordered_set < int > gg[N], f[N];
vi g[N], comp, G[N];
ll ans, S[N], s[N];


void dfs (int v, int p = 0) {
	fup[v] = tin[v] = ++timer;
	col[v] = k;
	++cnt[k];

	for (auto to : g[v]) {
		if (to == p)
			continue;
		if (tin[to])
			fup[v] = min(fup[v], tin[to]);
		else {
			dfs(to, v);
			fup[v] = min(fup[v], fup[to]);
			if (fup[to] > tin[v]) {
				gg[v].insert(to); 
				gg[to].insert(v);
			}
		}	
	}
}


void dfs1 (int v, int c) {
	col1[v]	= c;
	col2[c] = col[v];
	++cnt1[c];
	for (auto to : g[v])
		if (!col1[to] && !gg[v].count(to))
			dfs1(to, c);
}

void dfs2 (int v, int p = 0) {
	Cnt[v] = cnt1[v];
	
	Sz[col2[v]] += cnt1[v];
	par[v] = p;

	for (auto to : G[v])
		if (to != p) {
			dfs2(to, v); 
			Cnt[v] += Cnt[to];
		}					                     

}
 
ll get (int x) {
	return x * 1ll * (x - 1);
}

main () {	
	fastio
	cin >> n >> m;
	while (m--) {
		cin >> v >> u;
		g[v].pb(u);
		g[u].pb(v);
	}

	for (int i = 1; i <= n; ++i)
		if (!col[i]) {
			++k;
			dfs(i); 
			ans += cnt[k] * 1ll * (cnt[k] - 1) * (cnt[k] - 2);
		}




	for (int i = 1; i <= n; ++i)
		if (!col1[i]) {
			++kk;
			dfs1(i, kk); 
		}



	for (int i = 1; i <= n; ++i) {
		for (auto j : g[i])
			if (col1[i] != col1[j] && !f[col1[i]].count(col1[j])) {
				f[col1[i]].insert(col1[j]);
				G[col1[i]].pb(col1[j]);
			}	
	}			

	for (int i = 1; i <= kk; ++i)
		if (!Cnt[i]) 
			dfs2(i);

	for (int i = 1; i <= n; ++i) {
	    s[i] = 1;
	    for (auto j : g[i]) {
			if (col1[i] == col1[j])
				continue;
			int cur;
			if (Cnt[col1[i]] > Cnt[col1[j]])
				cur = Cnt[col1[j]];
			else
				cur = Cnt[col1[j]] - Cnt[col1[i]];
			s[i] += cur;
			ans -= get(cur);
	    }

		S[col1[i]] += get(s[i]);
	}

	for (int i = 1; i <= n; ++i) 
		ans -= S[col1[i]] - get(s[i]);		
	


	cout << ans << endl;
}                    

Compilation message (stderr)

count_triplets.cpp:101:7: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main () { 
       ^

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 8
• Subtask 4: 0 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10