Submission #761324

#	Time	Username	Problem	Language	Result	Execution time	Memory
761324		Sam_a17	Port Facility (JOI17_port_facility)	C++17	10 / 100	67 ms	96332 KiB

port_facility

///
#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
 
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;}
 
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(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, 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 << "]";}
 
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
 
// for random generations
// mt19937 myrand(chrono::steady_clock::now().time_since_epoch().count());
mt19937 myrand(373);
 
// 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 {
    // freopen("skis.in", "r", stdin);
    // freopen("skis.out", "w", stdout);
  }
}
// Indexed Set  
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const long long mod = 1e9 + 7;
const int N = 2e6 + 10;
vector<int> adj[N];
int st[N], en[N];
int vis[N];
int n;

void dfs(int node, int parent) {
  for(auto i: adj[node]) {
    if(vis[i]) {
      if(vis[i] != 3 - vis[node]) {
        cout << 0 << '\n';
        exit(0);
      }
      continue;
    }
    vis[i] = 3 - vis[node];
    dfs(i, node);
  }
}

long long binPowByMod(long long a, long long b) {
  a %= mod;
  long long res = 1;
  while (b > 0) {
    if (b & 1)
      res = res * a % mod;
    a = a * a % mod;
    b >>= 1;
  }
  return res;
}


void solve_() {
  cin >> n;

  vector<pair<int, int>> vec;
  for(int i = 1; i <= n; i++) {
    int a, b; cin >> a >> b;
    st[a] = i;
    en[b] = i;

    //
    vec.emplace_back(a, b);
  }

  int add = 0;
  for(int it = 0; it < sz(vec); it++) {
    for(int i = vec[it].first + 1; i < vec[it].second; i++) {
      if(st[i]) {
        int cur = st[i] - 1;
        if(vec[cur].second > vec[it].second) {
          adj[it].push_back(cur);
          add++;
        }
      } else {
        int cur = en[i] - 1;
        if(vec[cur].first < vec[it].first) {
          adj[it].push_back(cur);
          add++;
        }
      }
    }
  }

  int cnt = 0;
  for(int i = 0; i < n; i++) {
    if(!vis[i]) {
      vis[i] = true;
      dfs(i, -1);
      cnt++;
    }
  }

  add /= 2;
  assert(add <= 5 * n);
  cout << binPowByMod(2, cnt) << '\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)

port_facility.cpp: In function 'void setIO(std::string)':
port_facility.cpp:70:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
port_facility.cpp:71:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 56
• Subtask 4: 0 / 22