結果

問題 No.274 The Wall
ユーザー fumiphys
提出日時 2019-10-27 20:26:47
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 20 ms / 2,000 ms
コード長 4,084 bytes
コンパイル時間 1,640 ms
コンパイル使用メモリ 168,608 KB
実行使用メモリ 7,324 KB
最終ジャッジ日時 2025-03-17 19:03:42
合計ジャッジ時間 2,462 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge5
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ファイルパターン 結果
sample AC * 4
other AC * 23
権限があれば一括ダウンロードができます

ソースコード

diff # 

// includes
#include <bits/stdc++.h>
using namespace std;

// macros
#define pb emplace_back
#define mk make_pair
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define irep(itr, st) for(auto itr = (st).begin(); itr != (st).end(); ++itr)
#define irrep(itr, st) for(auto itr = (st).rbegin(); itr != (st).rend(); ++itr)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define bit(n) (1LL<<(n))
// functions
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}
template <typename T> ostream &operator<<(ostream &os, const vector<T>& vec){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){os << p.first << " " << p.second; return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
//  types
using ll = long long int;
using P = pair<int, int>;
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1000000007;
const int dx[4] = {-1, 0, 1, 0};
const int dy[4] = {0, -1, 0, 1};
// io
struct fast_io{
  fast_io(){ios_base::sync_with_stdio(false); cin.tie(0); cout << fixed << setprecision(20);}
} fast_io_;


int m;
bool cross(int l1, int r1, int l2, int r2){
  if(r1 < l2)return false;
  if(r2 < l1)return false;
  return true;
}

pair<int, int> rev(int l, int r){
  return mk(m - 1 - r, m - 1 - l);
}

vector<P> edge[2010];
int color[2010];

bool dfs(int i){
  for(auto e: edge[i]){
    if(color[e.first] != 0){
      if(color[i] != color[e.first] * e.second)return false;
    }else{
      color[e.first] = color[i] * e.second;
      if(!dfs(e.first))return false;
    }
  }
  return true;
}

int main(int argc, char const* argv[])
{
  int n; cin >> n >> m;
  vector<int> l(n), r(n);
  rep(i, n)cin >> l[i] >> r[i];
  rep(i, n){
    rep(j, n){
      if(i == j)continue;
      if(cross(l[i], r[i], l[j], r[j])){
        int u, v; tie(u, v) = rev(l[j], r[j]);
        if(cross(l[i], r[i], u, v)){
          cout << "NO" << endl;
          return 0;
        }
        edge[i].pb(j, -1);
      }else{
        int u, v; tie(u, v) = rev(l[j], r[j]);
        if(cross(l[i], r[i], u, v)){
          edge[i].pb(j, 1);
        }
      }
    }
  }
  rep(i, n){
    if(color[i] == 0){
      color[i] = 1;
      if(!dfs(i)){
        cout << "NO" << endl;
        return 0;
      }
    }
  }
  cout << "YES" << endl;
  return 0;
}
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