제출 #292815

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
292815		BThero	Port Facility (JOI17_port_facility)	C++17	22 / 100	8 ms	384 KiB

port_facility

// chrono::system_clock::now().time_since_epoch().count()
#include<bits/stdc++.h>

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define debug(x) cerr << #x << " = " << x << endl;

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

const int MAXN = (int)2e3 + 5;
const int MOD = (int)1e9 + 7;

int addMod(int a, int b, int m = MOD) {
  a += b;
  
  if (m <= a) {
    a -= m;
  }
  
  return a;
}

int mulMod(int a, int b, int m = MOD) {
  return a * 1ll * b % m;
}

pii arr[MAXN];
int n;

namespace DSU {
  int par[MAXN], sz[MAXN], up[MAXN];
  
  void init(int n) {
    for (int i = 1; i <= n; ++i) {
      par[i] = i;
      sz[i] = 1;
      up[i] = 0;
    }
  }
  
  int get(int x, int &col) {
    while (x != par[x]) {
      col ^= up[x];
      x = par[x];
    }
    
    return x;
  }
  
  bool uni(int a, int b) {
    int path = 0;
    int na = get(a, path);
    int nb = get(b, path);
    
    if (na == nb) {
      return path == 1;
    }
    
    if (sz[na] < sz[nb]) {
      swap(a, b);
      swap(na, nb);
    }
    
    sz[na] += sz[nb];
    par[nb] = na;
    up[nb] = 1 - path;
    return 1;
  }
  
  int ans() {
    int ret = 1;
    
    for (int i = 1; i <= n; ++i) {
      if (par[i] == i) {
        ret = addMod(ret, ret);
      }
    }
    
    return ret;
  }
};

bool cmp(pii a, pii b) {
  return a.se < b.se;
}

void solve() {
  scanf("%d", &n);
  
  for (int i = 1; i <= n; ++i) {
    scanf("%d %d", &arr[i].fi, &arr[i].se);
  }
  
  sort(arr + 1, arr + n + 1, cmp);
  DSU::init(n);
  
  for (int i = 1; i <= n; ++i) {
    for (int j = i + 1; j <= n; ++j) {
      if (arr[i].fi < arr[j].fi && arr[i].se > arr[j].fi) {
        if (!DSU::uni(i, j)) {
          printf("0\n");
          return;
        }
      }
    }
  }
  
  printf("%d\n", DSU::ans());
}

int main() {
  int tt = 1;
  
  while (tt--) {
    solve();
  }

  return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

port_facility.cpp: In function 'void solve()':
port_facility.cpp:95:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   95 |   scanf("%d", &n);
      |   ~~~~~^~~~~~~~~~
port_facility.cpp:98:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   98 |     scanf("%d %d", &arr[i].fi, &arr[i].se);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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