Submission #547263

#	Time	Username	Problem	Language	Result	Execution time	Memory
547263		cig32	철인 이종 경기 (APIO18_duathlon)	C++17	0 / 100	129 ms	20396 KiB

count_triplets

#include "bits/stdc++.h"
using namespace std;
#define int long long
const int MAXN = 2e5 + 10;
const int MOD = 998244353;
#define ll __int128
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
  int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
ll read() { // read int128
  int x; cin >> x; return (ll)x;
}
long long bm(long long b, long long p) {
  if(p==0) return 1 % MOD;
  long long r = bm(b, p >> 1);
  if(p&1) return (((r*r) % MOD) * b) % MOD;
  return (r*r) % MOD;
}
long long inv(long long b) { 
  return bm(b, MOD-2);
}
long long f[MAXN];
long long nCr(int n, int r) { 
  long long ans = f[n]; ans *= inv(f[r]); ans %= MOD;
  ans *= inv(f[n-r]); ans %= MOD; return ans;
}
void precomp() { 
  for(int i=0; i<MAXN; i++) f[i] = (i == 0 ? 1 % MOD : (f[i-1] * i) % MOD);
}
int fastlog(int x) {
  if(x == 0) return -1;
  return 32 - __builtin_clz(x) - 1;
}
void gay(int i) {
  cout << "Case #" << i << ": ";
}
vector<int> adj[MAXN];
bool vis[MAXN];
int ans = 0;
int n;
int dfs(int node) {
  vis[node] = 1;
  int ret = 1;
  vector<int> v;
  for(int x: adj[node]) {
    if(vis[x]) continue;
    int q = dfs(x);
    v.push_back(q);
    ret+=q;
  }
  v.push_back(n-ret);
  for(int x: v) {
    ans += x * (n - x - 1);
  }
  return ret;
}
void solve(int tc) {
  int m;
  cin >> n >> m;
  for(int i=0; i<m; i++) {
    int u, v;
    cin >> u >> v;
    adj[u].push_back(v);
    adj[v].push_back(u);
  }
  for(int i=1; i<=n; i++) {
    if(!vis[i]) {
      dfs(i);
    }
  }
  cout << ans << '\n';
}
int32_t main(){
  precomp();
  //ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
} 
// I don't know geometry.

• 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