Submission #866406

#	Time	Username	Problem	Language	Result	Execution time	Memory
866406		mgl_diamond	Port Facility (JOI17_port_facility)	C++17	22 / 100	34 ms	20560 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ii = pair<int, int>;
 
#define foru(i, l, r) for(int i=(l); i<=(r); ++i)
#define ford(i, l, r) for(int i=(l); i>=(r); --i)
#define fore(x, v) for(auto &x : v)
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define fi first
#define se second
#define file "input"

void setIO() {
  ios::sync_with_stdio(0);
  cin.tie(0); cout.tie(0);
  if (fopen(file".inp", "r")) {
    freopen(file".inp", "r", stdin);
    freopen(file".out", "w", stdout);
  }
}

const int MOD = 1e9+7;
const int N = 1e5+5;

int n, evts[N], st[N], en[N];
vector<int> graph[N];
int cnt;
bool vis[N];
int color[N];

void dfs(int u) {
  vis[u] = 1;
  fore(v, graph[u]) {
    if (!vis[v]) { color[v] = color[u]^1; dfs(v); }
    else if (color[v] == color[u]) {
      cout << 0;
      exit(0);
    }
  }
}

int main() {
  setIO();
  cin >> n;

  foru(i, 1, n) {
    cin >> st[i] >> en[i];
    evts[st[i]] = i;
    evts[en[i]] = i;
  }

  foru(i, 1, n) 
    foru(j, 1, n)
      if (st[j] < st[i] && st[i] < en[j] && en[j] < en[i]) {
        graph[i].push_back(j);
        graph[j].push_back(i);
      }

  foru(i, 1, n) {
    if (vis[i]) continue;
    dfs(i);
    ++cnt;
  }

  int ans = 1;
  foru(i, 1, cnt) ans = ans * 2 % MOD;
  cout << ans;
}

Compilation message (stderr)

port_facility.cpp: In function 'void setIO()':
port_facility.cpp:19:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |     freopen(file".inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
port_facility.cpp:20:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |     freopen(file".out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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