結果

問題 No.2238 Rock and Hole
ユーザー kumakuma
提出日時 2023-02-04 10:25:38
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 97 ms / 3,000 ms
コード長 3,979 bytes
コンパイル時間 2,330 ms
コンパイル使用メモリ 207,356 KB
最終ジャッジ日時 2025-02-10 10:35:53
ジャッジサーバーID
（参考情報） 		judge5 / judge5
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ファイルパターン 結果
other AC * 24
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ソースコード

diff #
プレゼンテーションモードにする

#include <bits/stdc++.h>
// #include <atcoder/modint>
#define rng(a) a.begin(),a.end()
#define rrng(a) a.rbegin(),a.rend()
#define INF 2000000000000000000
#define ll long long
#define ull unsigned long long
#define ld long double
#define pll pair<ll, ll>
using namespace std;
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 (b<a) { a=b; return 1; } return 0; }
const double PI = 3.141592653589793238462643383279;
//=============dinic============================
ll MAX_V = 400000;
struct edge {ll to, cap, rev;};
vector<vector<edge>> G(MAX_V);
vector<ll> level(MAX_V);
vector<ll> iter(MAX_V);
void add_edge(ll from, ll to, ll cap = 1) {
  G.at(from).push_back((edge){to, cap, (ll)G.at(to).size()});
  G.at(to).push_back((edge){from, 0ll, (ll)G.at(from).size() - 1});
}
void bfs(ll s) {
  for (ll i = 0; i < MAX_V; ++i) {
    level.at(i) = -1;
  }
  queue<ll> q;
  level.at(s) = 0;
  q.push(s);
  while (!q.empty()) {
    ll v = q.front();
    q.pop();
    for (ll i = 0; i < G.at(v).size(); ++i) {
      edge &e = G.at(v).at(i);
      if (e.cap > 0 && level.at(e.to) < 0) {
        level.at(e.to) = level.at(v) + 1;
        q.push(e.to);
      }
    }
  }
}
ll dfs(ll v, ll t, ll f) {
  if (v == t) {
    return f;
  }
  for (ll &i = iter.at(v); i < G.at(v).size(); ++i) {
    edge &e = G.at(v).at(i);
    if (e.cap > 0 && level.at(v) < level.at(e.to)) {
      ll d = dfs(e.to, t, min(f, e.cap));
      if (d > 0) {
        e.cap -= d;
        G.at(e.to).at(e.rev).cap += d;
        return d;
      }
    }
  }
  return 0;
}
ll max_flow(ll s, ll t) {
  ll flow = 0;
  while (true) {
    bfs(s);
    if (level.at(t) < 0) {
      return flow;
    }
    for (ll i = 0; i < MAX_V; ++i) {
      iter.at(i) = 0;
    }
    ll f;
    while ((f = dfs(s, t, INF)) > 0) {
      flow += f;
    }
  }
  return flow;
}
//=================================================
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  ll H, W;
  cin >> H >> W;
  vector<string> S(H);
  for (ll i = 0; i < H; ++i) {
    cin >> S.at(i);
  }
  ll rock = 0, hole = 0;
  for (ll i = 0; i < H; ++i) {
    for (ll j = 0; j < W; ++j) {
      if (S.at(i).at(j) == 'r') {
        rock += 1;
      }
      if (S.at(i).at(j) == 'h') {
        hole += 1;
      }
    }
  }
  ll s = H * W, t = s + 1;
  for (ll i = 0; i < H; ++i) {
    pll before_l = {-1, -1};
    for (ll j = 0; j < W; ++j) {
      if (S.at(i).at(j) == 'h') {
        before_l = {i, j};
      }
      if (S.at(i).at(j) == 'r') {
        if (before_l != (pll){-1, -1}) {
          add_edge(before_l.first * W + before_l.second, i * W + j);
        }
      }
    }
    pll before_r = {-1, -1};
    for (ll j = W - 1; j >= 0; --j) {
      if (S.at(i).at(j) == 'h') {
        before_r = {i, j};
      }
      if (S.at(i).at(j) == 'r') {
        if (before_r != (pll){-1, -1}) {
          add_edge(before_r.first * W + before_r.second, i * W + j);
        }
      }
    }
  }
  for (ll j = 0; j < W; ++j) {
    pll before_u = {-1, -1};
    for (ll i = 0; i < H; ++i) {
      if (S.at(i).at(j) == 'h') {
        before_u = {i, j};
      }
      if (S.at(i).at(j) == 'r') {
        if (before_u != (pll){-1, -1}) {
          add_edge(before_u.first * W + before_u.second, i * W + j);
        }
      }
    }
    pll before_d = {-1, -1};
    for (ll i = H - 1; i >= 0; --i) {
      if (S.at(i).at(j) == 'h') {
        before_d = {i, j};
      }
      if (S.at(i).at(j) == 'r') {
        if (before_d != (pll){-1, -1}) {
          add_edge(before_d.first * W + before_d.second, i * W + j);
        }
      }
    }
  }
  for (ll i = 0; i < H; ++i) {
    for (ll j = 0; j < W; ++j) {
      if (S.at(i).at(j) == 'h') {
        add_edge(s, i * W + j);
      }
      else if(S.at(i).at(j) == 'r') {
        add_edge(i * W + j, t);
      }
    }
  }
  if (max_flow(s, t) == rock) {
    cout << "Yes" << "\n";
  }
  else {
    cout << "No" << "\n";
  }
}
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