Submission #49378

#	Time	Username	Problem	Language	Result	Execution time	Memory
49378		mirbek01	Duathlon (APIO18_duathlon)	C++17	0 / 100	596 ms	35388 KiB

count_triplets

# include <bits/stdc++.h>

using namespace std;

const int N = 1e5 + 2;

int n, m, used[4][N], root;
int tin[N], fup[N], timer;
int p[N], sz[N], siz[N];
long long ans;
map < pair <int, int>, bool > isb;
vector <int> g[N], gr[N], vr[N];

void dfs(int v, int pr = 0){
      used[0][v] = 1;
      tin[v] = fup[v] = ++ timer;
      for(int to : g[v]){
            if(to == pr) continue;
            if(used[0][to])
                  fup[v] = min(fup[v], tin[to]);
            else {
                  dfs(to, v);
                  fup[v] = min(fup[v], fup[to]);
                  if(fup[to] > tin[v]){
                        isb[{v, to}] = 1;
                        isb[{to, v}] = 1;
                  }
            }
      }
}

int get(int v){
      return (p[v] == v)?v:p[v] = get(p[v]);
}

void unite(int a, int b){
      a = get(a);
      b = get(b);
      if(a != b){
            if(sz[b] > sz[a]) swap(a, b);
            p[b] = a;
            sz[a] += sz[b];
      }
}

void dfs1(int v){
      used[1][v] = 1;
      for(int to : g[v]){
            if(used[1][to]) continue;
            if(!isb[{v, to}])
                  unite(v, to);
            dfs1(to);
      }
}

void dfs2(int v){
      used[2][v] = 1;
      vr[get(v)].push_back(v);
      for(int to : g[v]){
            if(used[2][to]) continue;
            if(get(v) != get(to)){
                  gr[get(v)].push_back(get(to));
                  gr[get(to)].push_back(get(v));
            }
            dfs2(to);
      }
}

void dfs3(int v){
      used[3][v] = 1;
      sort(gr[v].begin(), gr[v].end());
      gr[v].resize(unique(gr[v].begin(), gr[v].end()) - gr[v].begin());
      siz[v] = sz[v];
      for(int to : gr[v]){
            if(used[3][to]) continue;
            dfs3(to);
            siz[v] += siz[to];
      }
}

void dfs4(int v, int pr = 0){
      ans += sz[v] * 1ll * (sz[v] - 1) * 1ll * (sz[v] - 2);
      ans += (siz[root] - siz[v]) * 1ll * (siz[v] - sz[v]) * 1ll * sz[v];
      long long cost = (sz[v] - 1) + (sz[v] - 1) * 1ll * (sz[v] - 2), S = 0;
      cost *= 2;
      ans += (siz[root] - siz[v]) * 1ll * cost;
      vector <int> vv;
      for(int i : vr[v]){
            vector <int> vec;
            for(int to : g[i])
                  if(get(to) != v)
                        vec.push_back(get(to));
            sort(vec.begin(), vec.end());
            vec.resize(unique(vec.begin(), vec.end()) - vec.begin());
            int sum = 0;
            for(int j : vec)
                  sum += sz[j];
            for(int j : vec)
                  ans += sz[j] * 1ll * (sum - sz[j]);
            vv.push_back(sum);
            S += sum;
      }
      for(int i : vv)
            ans += i * 1ll * (S - i);
      for(int to : gr[v]){
            if(to == pr) continue;
            ans += siz[to] * 1ll * cost;
            dfs4(to, v);
      }
}

int main(){
      scanf("%d %d", &n, &m);

      for(int i = 1; i <= m; i ++){
            int u, v;
            scanf("%d %d", &u, &v);
            g[u].push_back(v);
            g[v].push_back(u);
      }

      for(int i = 1; i <= n; i ++)
            p[i] = i, sz[i] = 1;

      for(int i = 1; i <= n; i ++){
            if(!used[0][i]){
                  dfs(i);
                  dfs1(i);
                  dfs2(i);
                  root = get(i);
                  dfs3(get(i));
                  dfs4(get(i));
            }
      }

      cout << ans << endl;
}

Compilation message (stderr)

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:113:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
       scanf("%d %d", &n, &m);
       ~~~~~^~~~~~~~~~~~~~~~~
count_triplets.cpp:117:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d %d", &u, &v);
             ~~~~~^~~~~~~~~~~~~~~~~

• 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