test/library_checker/graph/enumerate_triangles.test.cpp

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• Last update: 2022-07-20 01:50:04+09:00
• Problem: https://judge.yosupo.jp/problem/enumerate_triangles

Depends on

• 三角形列挙 (graph/enumerate_triangles.hpp)

Code

#define PROBLEM "https://judge.yosupo.jp/problem/enumerate_triangles"
#include <bits/stdc++.h>
using namespace std;
const long long MOD = 998244353;
#include "../../../graph/enumerate_triangles.hpp"
int main(){
  int N, M;
  cin >> N >> M;
  vector<long long> x(N);
  for (int i = 0; i < N; i++){
    cin >> x[i];
  }
  vector<vector<int>> E(N);
  for (int i = 0; i < M; i++){
    int u, v;
    cin >> u >> v;
    E[u].push_back(v);
    E[v].push_back(u);
  }
  vector<tuple<int, int, int>> T = enumerate_triangles(E);
  int cnt = T.size();
  long long ans = 0;
  for (int i = 0; i < cnt; i++){
    int a = get<0>(T[i]);
    int b = get<1>(T[i]);
    int c = get<2>(T[i]);
    ans += x[a] * x[b] % MOD * x[c] % MOD;
    ans %= MOD;
  }
  cout << ans << endl;
}

#line 1 "test/library_checker/graph/enumerate_triangles.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/enumerate_triangles"
#include <bits/stdc++.h>
using namespace std;
const long long MOD = 998244353;
#line 2 "graph/enumerate_triangles.hpp"
/**
 * @brief 三角形列挙
*/
vector<tuple<int, int, int>> enumerate_triangles(vector<vector<int>> &E){
  int N = E.size();
  vector<int> d(N);
  for (int i = 0; i < N; i++){
    d[i] = E[i].size();
  }
  vector<vector<int>> E2(N);
  for (int i = 0; i < N; i++){
    for (int j : E[i]){
      if (d[i] < d[j] || d[i] == d[j] && i < j){
        E2[i].push_back(j);
      }
    }
  }
  vector<bool> flg(N, false);
  vector<tuple<int, int, int>> ans;
  for (int i = 0; i < N; i++){
    for (int j : E2[i]){
      for (int k : E2[i]){
        flg[k] = true;
      }
      for (int k : E2[j]){
        if (flg[k]){
          ans.push_back(make_tuple(i, j, k));
        }
      }
      for (int k : E2[i]){
        flg[k] = false;
      }
    }
  }
  return ans;
}
#line 6 "test/library_checker/graph/enumerate_triangles.test.cpp"
int main(){
  int N, M;
  cin >> N >> M;
  vector<long long> x(N);
  for (int i = 0; i < N; i++){
    cin >> x[i];
  }
  vector<vector<int>> E(N);
  for (int i = 0; i < M; i++){
    int u, v;
    cin >> u >> v;
    E[u].push_back(v);
    E[v].push_back(u);
  }
  vector<tuple<int, int, int>> T = enumerate_triangles(E);
  int cnt = T.size();
  long long ans = 0;
  for (int i = 0; i < cnt; i++){
    int a = get<0>(T[i]);
    int b = get<1>(T[i]);
    int c = get<2>(T[i]);
    ans += x[a] * x[b] % MOD * x[c] % MOD;
    ans %= MOD;
  }
  cout << ans << endl;
}

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