Submission #598299

#	Time	Username	Problem	Language	Result	Execution time	Memory
598299		codebuster_10	Duathlon (APIO18_duathlon)	C++17	100 / 100	214 ms	44224 KiB

count_triplets

#include <bits/stdc++.h>
#define int int64_t //be careful about this 
 
using namespace std;
 
#define vt vector 
#define ar array 
#define pr pair 
 
#define f first 
#define s second
 
#define pb push_back
#define eb emplace_back
 
#define fr(i,a,b) for(int i = (a); i < (b); ++i)
#define rf(i,a,b) for(int i = (b)-1; i >= (a); --i)
#define all(x) x.begin(),x.end()
#define mem(a,b) memset(a,b,sizeof(a))
 
namespace IN{
  template<class T> void re(vector<T> &A);
  template<class S,class T> void re(pair<S,T> &A);
  template<class T,size_t N> void re(array<T,N> &A);
 
  template<class T> void re(T& x){ 
    cin >> x;}
  template<class H, class... T> void re(H& h, T&... t){ 
    re(h); re(t...);}
 
  template<class T> void re(vector<T> &A){ 
    for(auto& x : A) re(x);}
  template<class S,class T> void re(pair<S,T> &A){ 
      re(A.first); re(A.second);}
  template<class T,size_t N> void re(array<T,N> &A){
    for(int i = 0; i < N; ++i)  re(A[i]);}
}
 
namespace OUT{
  template<class T>
  void __p(const T& a){ cout<<a; }
  template<class T, class F>
  void __p(const pair<T, F>& a){ cout<<"{"; __p(a.first); cout<<","; __p(a.second); cout<<"}\n"; }
  template<class T, size_t N>
  void __p(const array<T,N>& a){ cout<<"{"; for(int i=0;i<N;++i)__p(a[i]),cout<<",}\n"[i+1==N]; }
  template<class T>
  void __p(const vector<T>& a){
    cout<<"{";for(auto it=a.begin();it<a.end();it++)__p(*it),cout<<",}\n"[it+1==a.end()]; }
  template<class T, class ...Arg>
  void __p(T a1, Arg ...a){__p(a1); __p(a...); }
  template<class Arg1>
  void __f(const char *s, Arg1 &&arg1){ cout<<s<<" : "; __p(arg1); cout<<endl; }
  template<class Arg1, class ... Args>
  void __f(const char *ss, Arg1 &&arg1, Args &&... args){
    int b=0,i=0; do{ if(ss[i]=='(') b++; if(ss[i]==')') b--; i++;}while(!(ss[i]==','&&b==0));
    const char *comma=ss+i; cout.write(ss,comma-ss)<<" : ";__p(arg1);cout<<" | ";__f(comma+1,args...);}
  #define trace(...) cout<<"Line:"<<__LINE__<<"  ", __f(#__VA_ARGS__, __VA_ARGS__)
}
 
 
namespace FUNC{
  void IO(string s = ""){
    ios_base::sync_with_stdio(NULL); 
    cin.tie(nullptr); 
    cout.precision(20); 
    cout << fixed;
    if(!s.empty()){
      freopen((s+".in").c_str(),"r",stdin);
      freopen((s+".out").c_str(),"w",stdout);
    }
  }
 
  const auto start_time = chrono::high_resolution_clock::now();
  void output_run_time(){
    // will work for ac,cc&&cf.
#ifndef ONLINE_JUDGE
    auto end_time = chrono::high_resolution_clock::now();
    chrono::duration<double> diff = end_time-start_time;
      cout << "\n\n\nTime Taken : " << diff.count();
#endif
  }
 
  template<class T> bool ckmin(T& a, const T& b){ 
    return b < a ? a = b, true : false; }
    
  template<class T> bool ckmax(T& a, const T& b){ 
    return a < b ? a = b, true : false; }
 
  mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
  int my_rand(int L, int R){ 
    return uniform_int_distribution<int>(L,R)(rng); }
  
  template<class T> int sz(const T& x){ 
    return int(x.size()); }
 
  template<class T> int lb(const vector<T>& vec,const T& val){
    return int(lower_bound(vec.begin(), vec.end(),val) - vec.begin()); }
 
  template<class T> int ub(const vector<T>& vec,const T& val){
    return int(upper_bound(vec.begin(), vec.end(),val) - vec.begin()); }
 
  constexpr int  dx[4] = {1,0,-1,0};
  constexpr int  dy[4] = {0,1,0,-1};
  constexpr char dr[4] = {'D','R','U','L'};
 
  constexpr long long INFLL1 = 1e16, INFLL2 = 9e18;
  constexpr int INF = 2e9;
 
  template<class T>
  vector<T> V(int n,T val){
    return vector<T> (n,val);
  }
 
  template<class T>
  vector<vector<T>> V(int n,int m,T val){
    return vector<vector<T>> (n,vector<T> (m,val));
  }
 
  template<class T>
  vector<vector<vector<T>>> V(int n,int m,int k,T val){
    return vector<vector<vector<T>>> (n,vector<vector<T>> (m,vector<T> (k,val)));
  }
}
 
 
using namespace IN;
using namespace OUT;
using namespace FUNC;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
struct edge{
  int to;
};
 
// returns {#bcc components, block tree}.
pair<int,vector<vector<int>>> bi_cc(const vector<vector<edge>> &g){
 
  int n = g.size();
 
  vector<int> depth(n,-1), low(n), comp;
  vector<vector<int>> block_tree(n);
  stack<int> s;
  int z = 0, f = -1;
 
  auto dfs = [&](auto self,int node,int parent) -> void {
    low[node] = depth[node];
 
    for(auto [child] : g[node])
      if(child != parent){
        if(depth[child] < 0){
          s.push(f); int here = f; --f;
          s.push(child); s.push(node);
          depth[child] = depth[node] + 1;
          self(self,child,node);
          if(low[child] >= depth[node]){
          
            while(comp.empty() || comp.back() != here)
              comp.push_back(s.top()), s.pop();
 
            sort(all(comp));
            comp.erase(unique(all(comp)),comp.end());
            
            for(auto i : comp) if(i >= 0) block_tree[i].pb(n+z);
 
            comp = {};
            z++;
          }
          low[node] = min(low[node],low[child]);
        }else if(depth[child] < depth[node]){
          s.push(child); s.push(node);
          low[node] = min(low[node],depth[child]);
        }
      }
    
    return;
  };
 
  for(int i = 0; i < n; ++i)
    if(depth[i] < 0){
      depth[i] = 0;
      dfs(dfs,i,-1);
    }
 
  block_tree.resize(z + n);
  fr(i,0,n){
    for(auto j : block_tree[i]){
      assert(j >= n);
      block_tree[j].pb(i);
    }
  } 
 
  return {z,block_tree};
}
 
 
 
signed main(){
  IO();
 
  int n,m;
  re(n,m);
 
  vt<vt<edge>> g(n);
  fr(e,0,m){
    int u,v; re(u,v); --u,--v;
    g[u].pb({v}); g[v].pb({u});
  }
 
  auto [z,block_tree] = bi_cc(g);
 
  vt<int> ss(z + n,0);
  vt<bool> vis(z + n, false);
 
  fr(i,0,n) ss[i] = 1;
 
  auto dfs = [&](auto self,int node,int parent) -> void {
    vis[node] = true;
    for(auto child : block_tree[node])
      if(child != parent){
        self(self,child,node);
        ss[node] += ss[child];
      }
  };  
 
  fr(i,0,z+n) if(!vis[i]) dfs(dfs,i,-1);
 
  fr(i,0,z+n) vis[i] = false;
 
  int ans = 0;
 
  auto re_root = [&](auto self,int node,int parent) -> void {
    vis[node] = true;
    if(node >= n){
      for(auto child : block_tree[node])
        ans -= (sz(block_tree[node]) - 1) * ss[child] * ss[child];
    }
    for(auto child : block_tree[node])
      if(child != parent){
        ss[node] -= ss[child];
        ss[child] += ss[node];
        self(self,child,node);
        ss[child] -= ss[node];
        ss[node] += ss[child];
      }
  };
 
  fr(i,0,z+n){
    if(!vis[i]){
      ans += ss[i] * (ss[i] - 1) * (ss[i] - 1);
      re_root(re_root,i,-1);
    }
  } 
 
  cout << ans;
 
 
  
  //output_run_time();
  return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void FUNC::IO(std::string)':
count_triplets.cpp:68:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |       freopen((s+".in").c_str(),"r",stdin);
      |       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:69:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |       freopen((s+".out").c_str(),"w",stdout);
      |       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• 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