Submission #969079

#	Time	Username	Problem	Language	Result	Execution time	Memory
969079		c2zi6	Duathlon (APIO18_duathlon)	C++14	23 / 100	1065 ms	1048576 KiB

count_triplets

#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define all(a) (a).begin(), (a).end()
#define replr(i, a, b) for (int i = int(a); i <= int(b); ++i)
#define reprl(i, a, b) for (int i = int(a); i >= int(b); --i)
#define rep(i, n) for (int i = 0; i < int(n); ++i)
#define mkp(a, b) make_pair(a, b)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<PII> VPI;
typedef vector<VI> VVI;
typedef vector<VVI> VVVI;
typedef vector<VPI> VVPI;
typedef pair<ll, ll> PLL;
typedef vector<ll> VL;
typedef vector<PLL> VPL;
typedef vector<VL> VVL;
typedef vector<VVL> VVVL;
typedef vector<VPL> VVPL;
template<class T> T setmax(T& a, T b) {if (a < b) return a = b; return a;}
template<class T> T setmin(T& a, T b) {if (a < b) return a; return a = b;}
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template<class T>
using indset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

int n, m;
VVI gp;

ll ans;
VI sbt;
VI vis;
int dfs1(int u, int p = -1) {
	vis[u] = true;
	sbt[u] = 1;
	for (int v : gp[u]) if (v != p) sbt[u] += dfs1(v, u);
	return sbt[u];
}
ll An2(ll n) {
	return n * (n-1);
}
void dfs2(int u, int p, int S) {
	VL a;
	a.pb(S - sbt[u]);
	for (int v : gp[u]) if (v != p) {
		dfs2(v, u, S);
		a.pb(sbt[v]);
	}
	ll cur = An2(S-1);
	for (ll x : a) cur -= An2(x);
	/* cout << u+1 << ": " << cur << endl; */
	ans += cur;
}


void solve() {
	cin >> n >> m;
	gp = VVI(n);
	rep(i, m) {
		int u, v;
		cin >> u >> v;
		u--, v--;
		gp[u].pb(v);
		gp[v].pb(u);
	}
	vis = sbt = VI(n);
	ans = 0;
	rep(u, n) if (!vis[u]) dfs1(u), dfs2(u, -1, sbt[u]);
	cout << ans << endl;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    int t = 1;
    // cin >> t;
    while (t--) solve();
}

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