Submission #713285

#	Time	Username	Problem	Language	Result	Execution time	Memory
713285		MohammadAghil	Duathlon (APIO18_duathlon)	C++17	0 / 100	428 ms	1048576 KiB

count_triplets

      #include <bits/stdc++.h>
//   #pragma GCC optimize ("Ofast,unroll-loops")
// #pragma GCC target ("avx2")
 using namespace std;
  typedef long long ll;
   typedef pair<int, int> pp;
     #define per(i,r,l) for(int i = (r); i >= (l); i--)
       #define rep(i,l,r) for(int i = (l); i < (r); i++)
          #define all(x) begin(x), end(x)
             #define sz(x) (int)(x).size()
                 #define pb push_back
                     #define ss second
                          #define ff first
                                  void err(istringstream *iss){}template<typename T,typename ...Args> void err(istringstream *iss,const T &_val, const Args&...args){string _name;*iss>>_name;if(_name.back()==',')_name.pop_back();cerr<<_name<<" = "<<_val<<", ",err(iss,args...);}
void IOS(){
     cin.tie(0) -> sync_with_stdio(0);
     #ifndef ONLINE_JUDGE
          #define er(args ...) cerr << __LINE__ << ": ", err(new istringstream(string(#args)), args), cerr << endl
          freopen("inp.txt", "r", stdin);
          freopen("out.txt", "w", stdout);
     #else
          #define er(args ...) 0
     #endif
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll mod = 998244353, maxn = 4e5 + 5, lg = 22, inf = ll(1e9) + 5;
ll pw(ll a,ll b,ll md=mod){if(!b)return 1;ll k=pw(a,b>>1ll,md);return k*k%md*(b&1ll?a:1)%md;}

struct DSU{
     int par[maxn], cnt[maxn];
     bool f = false;
     DSU(bool f): f(f){
          fill(par, par + maxn, -1);
          fill(cnt, cnt + maxn, 1);
     }
     int get(int x){
          return par[x] == -1? x: (f? par[x] = get(par[x]): get(par[x]));
     }
     vector<pp> his;
     void unite(int u, int v){
          u = get(u), v = get(v);
          if(u - v){
               if(cnt[u] < cnt[v]) swap(u, v);
               par[v] = u, cnt[u] += v;
               his.pb({u, v});
          } else his.pb({-1, -1});
     }
     void undo(){
          auto[u, v] = his.back(); his.pop_back();
          if(u + 1){
               par[v] = -1, cnt[u] -= cnt[v];
          }
     } 
} node(false), edge(true);


vector<pp> adj[maxn];
vector<int> str[maxn];
bool vis[maxn], act[maxn];

void dvd(int l, int r){
     if(l + 1 == r){
          vector<int> tmp;
          for(auto[c, e]: adj[l]){
               int x = node.get(c);
               tmp.pb(x);
               str[x].pb(e);
          }
          for(int x: tmp) if(!vis[x]){
               vis[x] = true;
               rep(i,1,sz(str[x])){
                    edge.unite(str[x][i-1], str[x][i]);
               } 
               str[x].clear();
          }
          for(int x: tmp) vis[x] = false;
          return;
     }
     int mid = (l + r)>>1;
     int cnt = 0;
     rep(i,mid,r){
          for(auto[c, e]: adj[i]){
               if(act[c]){
                    node.unite(i, c);
                    cnt++;
               }
          }
          act[i] = true;
     }
     dvd(l, mid);
     while(cnt--) node.undo();
     cnt = 0;
     rep(i,mid,r) act[i] = false;
     rep(i,l,mid){
          for(auto[c, e]: adj[i]){
               if(act[c]){
                    node.unite(i, c);
                    cnt++;
               }
          }
          act[i] = true;
     }
     dvd(mid, r);
     while(cnt--) node.undo();
     rep(i,l,mid) act[i] = false;
}

vector<int> adj2[maxn];
int m, cnt[maxn], val[maxn];
ll ans = 0;

void dfs(int r, int p){
     vis[r] = true;
     cnt[r] = r >= m;
     for(int c: adj2[r]) if(c - p){
          dfs(c, r);
          cnt[r] += cnt[c];
     }
}

void dfs2(int r, int p, int tot){
     if(r >= m){
          for(int c: adj2[r]) if(c - p){
               ans -= 1ll*(tot - cnt[c])*(tot - cnt[c] - 1)*(val[c] - 1);
          }
          if(p + 1){
               ans -= 1ll*(cnt[r])*(cnt[r]-1)*(val[p] - 1);
          }
     }
     for(int c: adj2[r]) if(c - p){
          dfs2(c, r, tot);
     }
}

int main(){ IOS();
     int n; cin >> n >> m;
     rep(i,0,m){
          int u, v; cin >> u >> v; u--, v--;
          adj[u].pb({v, i}), adj[v].pb({u, i});
     }
     dvd(0, n);
     rep(r,0,n){
          vector<int> tmp;
          for(auto[c, e]: adj[r]){
               int x = edge.get(e);
               if(!vis[x]){
                    val[x]++;
                    vis[x] = true;
                    tmp.pb(x);
                    adj2[x].pb(r + m);
                    adj2[r + m].pb(x);
               }
          }
          for(int x: tmp) vis[x] = false;
     }
     rep(i,m,n+m){
          if(!vis[i]){
               dfs(i, -1);
               ans += 1ll*cnt[i]*(cnt[i]-1)*(cnt[i]-2);
               dfs2(i, -1, cnt[i]);
          }
     }
     cout << ans << '\n';
     return 0-0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void IOS()':
count_triplets.cpp:19:18: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |           freopen("inp.txt", "r", stdin);
      |           ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:20:18: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |           freopen("out.txt", "w", stdout);
      |           ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• 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