Submission #1118706

#	Time	Username	Problem	Language	Result	Execution time	Memory
1118706		thieunguyenhuy	Duathlon (APIO18_duathlon)	C++17	100 / 100	188 ms	91472 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;

#define popcount(n) (__builtin_popcountll((n)))
#define clz(n) (__builtin_clzll((n)))
#define ctz(n) (__builtin_ctzll((n)))
#define lg(n) (63 - __builtin_clzll((n)))
#define BIT(n, i) (((n) >> (i)) & 1ll)
#define MASK(i) (1ll << (i))
#define FLIP(n, i) ((n) ^ (1ll << (i)))
#define ON(n, i) ((n) | MASK(i))
#define OFF(n, i) ((n) & ~MASK(i))

#define Int __int128
#define fi first
#define se second

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long long, int> pli;
typedef pair<int, long long> pil;
typedef vector<pair<int, int>> vii;
typedef vector<pair<long long, long long>> vll;
typedef vector<pair<long long, int>> vli;
typedef vector<pair<int, long long>> vil;

template <class T1, class T2>
bool maximize(T1 &x, T2 y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}
template <class T1, class T2>
bool minimize(T1 &x, T2 y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}

template <class T>
void remove_duplicate(vector<T> &ve) {
    sort (ve.begin(), ve.end());
    ve.resize(unique(ve.begin(), ve.end()) - ve.begin());
}

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
template <class T> T random(T l, T r) {
    return uniform_int_distribution<T>(l, r)(rng);
}
template <class T> T random(T r) {
    return rng() % r;
}

const int N = 1e6 + 5;
const int MOD = 1e9 + 7;
const int inf = 1e9;
const long long INF = 1e18;

int n, m, dfsTime = 0, cnt = 0, numBCCs = 1;
int low[N], num[N], sz[N];
ll ans = 0;
vector<int> adj[N], ke[N + N];
stack<int> st;

void dfs(int u, int fa) {
	low[u] = num[u] = ++dfsTime; ++cnt, st.emplace(u);
	for (auto v : adj[u]) {
		if (!num[v]) {
			dfs(v, u); minimize(low[u], low[v]);
			if (low[v] >= num[u]) {
				ke[u].emplace_back(n + numBCCs);
				while (st.top() != v) {
					ke[n + numBCCs].emplace_back(st.top());
					st.pop();
				}
				ke[n + numBCCs].emplace_back(st.top());
				st.pop(); ++numBCCs;
			}
		}
		else if (v != fa) minimize(low[u], num[v]);
	}
}

void dfsAns(int u) {
	// cerr << u << '\n';
	sz[u] = (u <= n);
	for (auto v : ke[u]) {
		dfsAns(v); sz[u] += sz[v];
		if (u > n) ans -= 1ll * ke[u].size() * sz[v] * (sz[v] - 1);
	}
	if (u > n) ans -= 1ll * ke[u].size() * (cnt - sz[u]) * (cnt - sz[u] - 1);
}

signed main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

    cin >> n >> m;

    for (int i = 1; i <= m; ++i) {
    	int u, v; cin >> u >> v;
    	adj[u].emplace_back(v), adj[v].emplace_back(u);
    }

    for (int i = 1; i <= n; ++i) if (num[i] == 0) {
    	cnt = 0; dfs(i, -1);
    	ans += 1ll * cnt * (cnt - 1) * (cnt - 2);
    	dfsAns(i);
    }

    cout << ans << '\n';
    cerr << '\n'; return 0;
}

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