제출 #64859

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
64859		qkxwsm	철인 이종 경기 (APIO18_duathlon)	C++17	66 / 100	355 ms	48108 KiB

count_triplets

/*
PROG: source
LANG: C++11
_____
.'     '.
/  0   0  \
|     ^     |
|  \     /  |
\  '---'  /
'._____.'
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

struct chash
{
        int operator()(int x) const
        {
                x ^= (x >> 20) ^ (x >> 12);
                return x ^ (x >> 7) ^ (x >> 4);
        }
        int operator()(long long x) const
        {
                return x ^ (x >> 32);
        }
};

template<typename T> using orderedset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T> using hashtable = gp_hash_table<T, T, chash>;

template<class T>
void readi(T &x)
{
        T input = 0;
        bool negative = false;
        char c = ' ';
        while (c < '-')
        {
                c = getchar();
        }
        if (c == '-')
        {
                negative = true;
                c = getchar();
        }
        while (c >= '0')
        {
                input = input * 10 + (c - '0');
                c = getchar();
        }
        if (negative)
        {
                input = -input;
        }
        x = input;
}
template<class T>
void printi(T output)
{
        if (output == 0)
        {
                putchar('0');
                return;
        }
        if (output < 0)
        {
                putchar('-');
                output = -output;
        }
        int aout[20];
        int ilen = 0;
        while(output)
        {
                aout[ilen] = ((output % 10));
                output /= 10;
                ilen++;
        }
        for (int i = ilen - 1; i >= 0; i--)
        {
                putchar(aout[i] + '0');
        }
        return;
}
template<class T>
void ckmin(T &a, T b)
{
        a = min(a, b);
}
template<class T>
void ckmax(T &a, T b)
{
        a = max(a, b);
}
template<class T>
T normalize(T x, T mod = 1000000007)
{
        return (((x % mod) + mod) % mod);
}
long long randomizell(long long mod)
{
        return ((1ll << 45) * rand() + (1ll << 30) * rand() + (1ll << 15) * rand() + rand()) % mod;
}
int randomize(int mod)
{
        return ((1ll << 15) * rand() + rand()) % mod;
}

#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define PF push_front
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define debug(x) cerr << #x << " = " << x << endl;

const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-10;

#define MAGIC 347
#define SINF 10007
#define CO 1000007
#define INF 1000000007
#define BIG 1000000931
#define LARGE 1696969696967ll
#define GIANT 2564008813937411ll
#define LLINF 2696969696969696969ll
#define MAXN 200013

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

int N, M, T, K;
vector<int> edge[MAXN], edge1[MAXN];
int sz[MAXN];
vector<pii> bridge;
vector<pii> edges;
bool ap[MAXN];
vector<int> bcc[MAXN];
int id[MAXN], aid[MAXN];
int parent[MAXN];
int subtree[MAXN];
int disc[MAXN], low[MAXN];
int dsu[MAXN], dsz[MAXN];
vector<int> nodes[MAXN];
bool seen[MAXN];
ll ans = 0, tot = 0;

int find_parent(int u)
{
        return (u == dsu[u] ? u : dsu[u] = find_parent(dsu[u]));
}
void merge(int u, int v)
{
        u = find_parent(u);
        v = find_parent(v);
        if (u == v) return;
        if (dsz[u] > dsz[v])
        {
                swap(u, v);
        }
        dsz[v] += dsz[u];
        dsz[u] = 0;
        dsu[u] = v;
        return;
}
void dfs(int u, bool head = false)
{
        disc[u] = T;
        low[u] = T;
        seen[u] = true;
        T++;
        int children = 0;
        for (int v : edge[u])
        {
                if (v == parent[u])
                {
                        continue;
                }
                if (seen[v])
                {
                        ckmin(low[u], low[v]);
                        continue;
                }
                children++;
                parent[v] = u;
                edges.PB({u, v});
                dfs(v);
                ckmin(low[u], low[v]);
                if (low[v] >= disc[u])
                {
                        if (low[v] != disc[u])
                        {
                                bridge.PB({u, v});
                        }
                        if (!head)
                        {
                                ap[u] = true;
                                while(edges.back() != MP(u, v))
                                {
                                        bcc[K].PB(edges.back().fi);
                                        bcc[K].PB(edges.back().se);
                                        edges.pop_back();
                                }
                                bcc[K].PB(edges.back().fi);
                                bcc[K].PB(edges.back().se);
                                edges.pop_back();
                                K++;
                        }
                }
                if (head)
                {
                        if (children > 1)
                        {
                                ap[u] = true;
                        }
                        while(edges.back() != MP(u, v))
                        {
                                bcc[K].PB(edges.back().fi);
                                bcc[K].PB(edges.back().se);
                                edges.pop_back();
                        }
                        bcc[K].PB(edges.back().fi);
                        bcc[K].PB(edges.back().se);
                        edges.pop_back();
                        K++;
                }
        }
}
void dfs1(int u)
{
        subtree[u] = sz[u];
        for (int v : edge1[u])
        {
                if (v == parent[u])
                {
                        continue;
                }
                parent[v] = u;
                dfs1(v);
                subtree[u] += subtree[v];
        }
        return;
}

int32_t main()
{
        ios_base::sync_with_stdio(0);
        srand(time(0));
        //	cout << fixed << setprecision(10);
        //	cerr << fixed << setprecision(10);
        if (fopen("input.in", "r"))
        {
                freopen ("input.in", "r", stdin);
                freopen ("output.out", "w", stdout);
        }
        cin >> N >> M;
        for (int i = 0; i < N; i++)
        {
                dsu[i] = i;
                dsz[i] = i;
        }
        for (int i = 0; i < M; i++)
        {
                int u, v;
                cin >> u >> v;
                u--; v--;
                edge[u].PB(v);
                edge[v].PB(u);
                merge(u, v);
        }
        for (int i = 0; i < N; i++)
        {
                parent[i] = N;
        }
        for (int i = 0; i < N; i++)
        {
                nodes[find_parent(i)].PB(i);
        }
        for (int cc = 0; cc < N; cc++)
        {
                if (find_parent(cc) != cc)
                {
                        continue;
                }
                int n = nodes[cc].size();
                dfs(cc, 1);
                for (int i = 0; i < K; i++)
                {
                        sort(bcc[i].begin(), bcc[i].end());
                        bcc[i].erase(unique(bcc[i].begin(), bcc[i].end()), bcc[i].end());
                        // cerr << "bcc # " << i << ":";
                        for (int u : bcc[i])
                        {
                                // cerr << ' ' << u;
                                id[u] = i;
                                if (!ap[u])
                                {
                                        sz[i]++;
                                }
                        }
                        // cerr << endl;
                }
                for (int i = 0; i < n; i++)
                {
                        int u = nodes[cc][i];
                        if (ap[u])
                        {
                                aid[u] = K;
                                sz[K] = 1;
                                K++;
                                // cerr << "ap " << i << " id " << K - 1 << endl;
                        }
                }
                for (int i = 0; i < K; i++)
                {
                        // cerr << "bcc " << i << ":";
                        for (int u : bcc[i])
                        {
                                // cerr << ' ' << u;
                                if (ap[u])
                                {
                                        edge1[i].PB(aid[u]);
                                        edge1[aid[u]].PB(i);
                                }
                        }
                        // cerr << endl;
                }
                // for (int i = 0; i < K; i++)
                // {
                //         for (int u : edge1[i])
                //         {
                //                 if (i <= u) cerr << i << " -> " << u << endl;
                //         }
                // }
                // for (int i = 0; i < K; i++)
                // {
                //         cerr << sz[i] << ' ';
                // }
                // cerr << endl;
                for (int i = 0; i < K; i++)
                {
                        parent[i] = K;
                }
                dfs1(0);
                //all 3 distinct blocks
                //the only violations allowed are: guy -> ap in u -> u
                for (int i = 0; i < K; i++)
                {
                        tot += 1ll * (n - sz[i]) * sz[i] * (n - sz[i] - 1);
                        if (bcc[i].empty())
                        {
                                for (int v : edge1[i])
                                {
                                        for (int w : edge1[v])
                                        {
                                                if (w == i) continue;
                                                if (w == parent[v]) continue;
                                                // if (i == 4) cerr << w << 'X' << v << endl;
                                                tot -= 1ll * subtree[w] * (subtree[w] - 1);
                                        }
                                        // tot -= 1ll * (n - subtree[parent[v]]) * (n - subtree[parent[v]] - 1);
                                }
                                tot -= 1ll * (n - subtree[parent[i]]) * (n - subtree[parent[i]] - 1);
                        }
                        else
                        {
                                for (int v : edge1[i])
                                {
                                        if (v == parent[i]) continue;
                                        tot -= 1ll * sz[i] * (subtree[v]) * (subtree[v] - 1);
                                }
                                tot -= 1ll * sz[i] * (n - subtree[i]) * (n - subtree[i] - 1);
                        }
                        // cerr << "after center " << i << " get " << tot << endl;
                        // tot += 2ll * sz[i] * (n - subtree[i]) * (subtree[i] - sz[i]);
                }
                // debug(tot);
                //three equal guys
                for (int i = 0; i < K; i++)
                {
                        tot += 1ll * sz[i] * (sz[i] - 1) * (sz[i] - 2);
                }
                // debug(tot);
                //a=b or b=c BUT NOT BOTH!
                for (int i = 0; i < K; i++)
                {
                        tot += 2ll * sz[i] * (sz[i] - 1) * (n - sz[i]);
                }
                // debug(tot);
                if (sz[0] == n)
                {
                        ans += 1ll * n * (n - 1) * (n - 2);
                }
                else
                {
                        ans += tot;
                }
                for (int i = 0; i < K; i++)
                {
                        bcc[i].clear();
                        sz[i] = 0;
                        edge1[i].clear();
                        subtree[i] = 0;
                }
                K = 0; T = 0; tot = 0;
        }
        // for (int i = 0; i < K; i++)
        // {
        //     for (int v : edge1[i])
        //     {
        //         cerr << i << "->" << v << endl;
        //     }
        //     cerr << "size " << i << " = " << sz[i] << endl;
        // }
        // for (int i = 0; i < K; i++)
        // {
        //         cerr << "subtree " << i << "=" << subtree[i] << endl;
        // }
        //if a -> b must pass through c, then: a -> b -> c is bad; c -> b -> a is bad, c -> a -> b is bad, b -> a -> c
        //three separate components
        cout << ans << '\n';
        //	cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
        return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

count_triplets.cpp: In function 'int32_t main()':
count_triplets.cpp:264:25: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
                 freopen ("input.in", "r", stdin);
                 ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:265:25: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
                 freopen ("output.out", "w", stdout);
                 ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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