Submission #1123290

#	Time	Username	Problem	Language	Result	Execution time	Memory
1123290		Denisov	Duathlon (APIO18_duathlon)	C++20	0 / 100	103 ms	35272 KiB

count_triplets

//#pragma GCC optimize("Ofast", "unroll-loops")
//#pragma GCC target("sse", "sse2", "sse3", "ssse3", "sse4")

#include <bits/stdc++.h>

#define all(a) a.begin(),a.end()
#define len(a) (int)(a.size())
#define mp make_pair
#define pb push_back
#define fir first
#define sec second
#define fi first
#define se second

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;

template<typename T>
bool umin(T &a, T b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}
template<typename T>
bool umax(T &a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

#ifdef KIVI
#define DEBUG for (bool _FLAG = true; _FLAG; _FLAG = false)
#define LOG(...) print(#__VA_ARGS__" ::", __VA_ARGS__) << endl
template <class ...Ts> auto &print(Ts ...ts) { return ((cerr << ts << " "), ...); }
#else
#define DEBUG while (false)
#define LOG(...)
#endif

const int max_n = (1e5 + 11) * 2, inf = 1000111222;

vector <int> edge[max_n];

int tin[max_n], tout[max_n], used[max_n], timer = 0, art[max_n], id[max_n];


vector <int> q;

vector <vector <int> > cmp;

inline void dfs (int v, int p = -1) {
    used[v] = 1;
    tin[v] = timer++;
    tout[v] = tin[v];
    q.pb(v);
    for (int to : edge[v]) {
        if (to == p) {
            continue;
        }
        if (used[to]) {
            umin(tout[v], tin[to]);
        }
        else {
            dfs(to, v);
            umin(tout[v], tout[to]);
            if (tout[to] >= tin[v]) {
                art[v] = tin[v] > 0 || tin[to] > 1;
                cmp.pb(vector <int>{v});
                while (cmp.back().back() != to) {
                    cmp.back().pb(q.back());
                    q.pop_back();
                }
            }
        }
    }
}

struct dsu {
public:
    int n;
    vector <int> p, cnt;

    inline void make_set (int v) {
        p[v] = v;
    }

    dsu (int n) : n(n) {
        p.resize(n);
        cnt.assign(n, 1);
        for (int i = 0; i < n; i++) {
            make_set(i);
        }
    }

    inline int get (int v) {
        if (p[v] == v) return v;
        return p[v] = get(p[v]); /// compressing path
    }

    inline bool unite (int a, int b) {
        a = get(a);
        b = get(b);
        if (a == b) return false;
        if (cnt[a] > cnt[b]) {
            swap(a, b);
        }
        p[a] = b;
        cnt[b] += cnt[a];
        return true;
    }
};

vector <int> e[max_n];

int sz[max_n], n;



ll res[max_n];

ll ans = 0;

inline void calc (int v, int p = -1) {
    ans += sz[v] * (sz[v] - 1ll) * (sz[v] - 2ll);
    ans += sz[v] * (sz[v] - 1ll) * (n - sz[v]) * 2ll;
    ll cur = sz[v];
    for (int to : e[v]) {
        if (to == p) {
            continue;
        }
        calc(to, v);
        ans += cur * sz[to] * (sz[v] - cur) * 2ll;
        sz[v] += sz[to];
    }
    ans += cur * (sz[v] - cur) * (n - sz[v]) * 2ll;
}


int main() {
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);

    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int m;
    cin >> n >> m;
    for (int i = 0, a, b; i < m; i++) {
        a = i + 1, b = i + 2;
        cin >> a >> b;
        --a, --b;
        edge[a].pb(b);
        edge[b].pb(a);
    }
    dfs(0);
    int new_id = 0;
    for (int i = 0; i < n; i++) {
        if (art[i]) {
            id[i] = new_id++;
        }
    }
    for (auto &i : cmp) {
        int now = new_id++, cnt = 0;
        for (int x : i) {
            if (art[x]) {
                e[id[x]].pb(now);
                e[now].pb(id[x]);
                LOG(id[x], now);
            }
            else {
                ++cnt;
                id[x] = now;
            }
        }
        for (int x : i) {
            if (art[x]) {
                ans += cnt * (cnt - 1ll);
            }
        }
    }
    LOG(new_id);
    for (int i = 0; i < n; i++) {
        ++sz[id[i]];
    }
    calc(0);
    cout << ans << '\n';
}

• 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