Submission #69351

#	Time	Username	Problem	Language	Result	Execution time	Memory
69351		Just_Solve_The_Problem	Port Facility (JOI17_port_facility)	C++11	100 / 100	2173 ms	624352 KiB

port_facility

#include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define eb emplace_back
#define ll long long
#define pii pair < int, int >
#define fr first
#define sc second
#define mk make_pair
#define sz(s) (int)s.size()
#define all(s) s.begin(), s.end()
#define OK puts("ok");
#define whatis(x) cerr << #x << " = " << x << endl;
#define pause system("pause");

const int N = (int)2e6 + 7;
const int inf = (int)1e9 + 7;
int mod = (int)1e9 + 7;

pii ar[N];
int pr[N], used[N];
int ans;
map < int, int > mp;

int mult(int a, int b) {
  return (a * 1LL * b) % mod;
}

int getpar(int a) {
  if (pr[a] == a) return a;
  return pr[a] = getpar(pr[a]);
}

void connect(int a, int b) {
  a = getpar(a);
  b = getpar(b);
  if (a != b) {
    pr[a] = b;
  }
}

main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d %d", &ar[i].fr, &ar[i].sc);
  }
  iota(pr, pr + n + n + 2, 0);
  sort(ar, ar + n);
  int ans = 1;
  for (int i = 0; i < n; i++) {
    auto fir = mp.lower_bound(ar[i].fr), sec = mp.lower_bound(ar[i].sc);
    while (fir != sec) {
      connect(i, (fir -> sc) + n);
      connect(i + n, fir -> sc);
      if (getpar((--sec) -> sc) == getpar(fir -> sc))
        break;
      fir++;
      sec++;
    }
    mp[ar[i].sc] = i;
  }
  for (int i = 0; i < n; i++) {
    if (getpar(i) == getpar(i + n)) ans = 0;
    else used[getpar(i)] = used[getpar(i + n)] = 1;
  }
  for (int i = 0; i < n; i++) {
    if (used[i]) {
      ans = mult(ans, 2);
    }
  }
  cout << ans;
}

Compilation message (stderr)

port_facility.cpp:44:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^
port_facility.cpp: In function 'int main()':
port_facility.cpp:46:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &n);
   ~~~~~^~~~~~~~~~
port_facility.cpp:48:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &ar[i].fr, &ar[i].sc);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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