Submission #771731

#	Time	Username	Problem	Language	Result	Execution time	Memory
771731		Sam_a17	Duathlon (APIO18_duathlon)	C++17	5 / 100	1113 ms	888636 KiB

count_triplets

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;
 
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
 
#define sz(x) (int)x.size()
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define blt __builtin_popcount
 
#define pb push_back
#define popf pop_front
#define popb pop_back
#define ld long double
#define ll long long
 
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
 
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
 
// Indexed Set  
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
 
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
// template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(Tree <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
 
 
// for random generations
mt19937 myrand(chrono::steady_clock::now().time_since_epoch().count());
// mt19937 myrand(131);
 
// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
 
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();
 
  if(str == "input") {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
  } else if(str != "") {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
  }
}

const int N = 2e5 + 10;
vector<int> adj[N];
bool vis[N], vis2[N];
int dp[51][51][51];
long long n, m, ans;
int st;

void dfs_slow(int node, vector<int> &cur, int d = 0) {
  vis[node] = true;
  
  if(d >= 2) {
    for(int i = 1; i < sz(cur) - 1; i++) {
      dp[st][cur[i]][node] = 1;
    }
  }

  for(auto i: adj[node]) {
    if(vis[i]) continue;
    cur.push_back(i);
    dfs_slow(i, cur, d + 1);
    cur.pop_back();
  }
  vis[node] = false;
}

long long sub[N];
void dfs(int node, int parent) {
  sub[node] = 1;
  for(auto i: adj[node]) {
    if(i == parent) continue;
    dfs(i, node);
    sub[node] += sub[i];
  }
}

void solve_() {
  cin >> n >> m;

  for(int i = 1; i <= m; i++) {
    int a, b; cin >> a >> b;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }

  if(n <= 10) {
    for(int i = 1; i <= n; i++) {
      st = i;
      vector<int> vec{i};
      dfs_slow(i, vec);
    }

    for(int i = 1; i <= n; i++) {
      for(int j = 1; j <= n; j++) {
        for(int k = 1; k <= n; k++) {
          ans += dp[i][j][k];
        }
      }
    }

    cout << ans << '\n';
  } else {
    ans = 0;
    for(int i = 1; i <= n; i++) {
      dfs(i, 0);
      assert(sub[i] == n);

      long long al = sub[i] - 1;
      for(auto j: adj[i]) {
        ans += (al - sub[j]) * sub[j];
        al -= sub[j];
      }

    }
    cout << ans << '\n';
  }
}
 
int main() {
  setIO();
 
  auto solve = [&](int test_case)-> void {
    for(int i = 1; i <= test_case; i++) {
      solve_();
    }
  };
 
  int test_cases = 1;
  // cin >> test_cases;
  solve(test_cases);
 
  return 0;
} 

Compilation message (stderr)

count_triplets.cpp: In function 'void setIO(std::string)':
count_triplets.cpp:76:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:77:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:79:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   79 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:80:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   80 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 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