結果

問題 No.2464 To DAG
コンテスト
ユーザー hos.lyric
提出日時 2023-09-08 22:13:19
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
WA  
実行時間 -
コード長 4,909 bytes
コンパイル時間 1,463 ms
コンパイル使用メモリ 115,140 KB
実行使用メモリ 38,404 KB
最終ジャッジ日時 2024-06-26 15:18:00
合計ジャッジ時間 15,550 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge1
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 1 WA * 1
other AC * 5 WA * 7 RE * 11 TLE * 1 -- * 15
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 # 

#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")


template <class Flow> struct MaxFlow {
  // Watch out when using types other than int and long long.
  static constexpr Flow FLOW_EPS = 1e-10L;
  static constexpr Flow FLOW_INF = std::numeric_limits<Flow>::max();
  
  int n, m;
  vector<int> ptr, nxt, zu;
  vector<Flow> capa;

  explicit MaxFlow(int n_) : n(n_), m(0), ptr(n_, -1) {}
  void ae(int u, int v, Flow w0, Flow w1 = 0) {
    assert(0 <= u); assert(u < n);
    assert(0 <= v); assert(v < n);
    assert(0 <= w0);
    assert(0 <= w1);
    nxt.push_back(ptr[u]); zu.push_back(v); capa.push_back(w0); ptr[u] = m++;
    nxt.push_back(ptr[v]); zu.push_back(u); capa.push_back(w1); ptr[v] = m++;
  }

  vector<int> see, lev, que;

  Flow augment(int u, int t, Flow limFlow) {
    if (u == t) return limFlow;
    for (int &i = see[u]; ~i; i = nxt[i]) if (capa[i] > FLOW_EPS) {
      const int v = zu[i];
      if (lev[u] < lev[v]) {
        const Flow f = augment(v, t, min(limFlow, capa[i]));
        if (f > FLOW_EPS) { capa[i] -= f; capa[i ^ 1] += f; return f; }
      }
    }
    return 0;
  }
  bool bfs(int s, int t) {
    for (int u = 0; u < n; ++u) { see[u] = ptr[u]; lev[u] = -1; }
    auto head = que.begin(), tail = que.begin();
    for (lev[*tail++ = s] = 0; head != tail; ) {
      const int u = *head++;
      for (int i = ptr[u]; ~i; i = nxt[i]) if (capa[i] > FLOW_EPS) {
        const int v = zu[i];
        if (!~lev[v]) {
          lev[*tail++ = v] = lev[u] + 1;
          if (v == t) return true;
        }
      }
    }
    return false;
  }
  Flow run(int s, int t, Flow limFlow = FLOW_INF) {
    see.resize(n); lev.resize(n); que.resize(n);
    Flow flow = 0;
    for (; flow + FLOW_EPS < limFlow && bfs(s, t); ) {
      for (Flow f; (f = augment(s, t, limFlow - flow)) > FLOW_EPS; flow += f) {}
    }
    return flow;
  }
};

////////////////////////////////////////////////////////////////////////////////


int N, M;
vector<int> A, B;

vector<set<int>> G;
vector<int> bal;

vector<int> ans;
vector<int> prei;

int main() {
  for (; ~scanf("%d%d", &N, &M); ) {
    A.resize(M);
    B.resize(M);
    for (int i = 0; i < M; ++i) {
      scanf("%d%d", &A[i], &B[i]);
      --A[i];
      --B[i];
    }
    
    G.assign(N, {});
    for (int i = 0; i < M; ++i) {
      G[A[i]].insert(i);
    }
    bal.assign(N, 0);
    for (int i = 0; i < M; ++i) {
      ++bal[A[i]];
      --bal[B[i]];
    }
// cerr<<"bal = "<<bal<<endl;
    ans.clear();
    prei.assign(N, -1);
    for (int u = 0; u < N; ++u) {
      for (; bal[u] > 0; ) {
// cerr<<"u = "<<u<<"; prei = "<<prei<<endl;
        for (int v = u; ; ) {
// cerr<<"  v = "<<v<<"; prei = "<<prei<<endl;
          // path
          if (bal[v] < 0) {
            ++bal[v];
            for (int w = v; w != u; ) {
// cerr<<"  path "<<w<<endl;
              const int i = prei[w];
              prei[w] = -1;
              ans.push_back(i);
              G[A[i]].erase(i);
              w = A[i];
            }
            --bal[u];
            break;
          }
          assert(!G[v].empty());
          const int i = *G[v].begin();
          const int w = B[i];
          // cycle
          if (~prei[w]) {
// cerr<<"  cycle! "<<A[i]<<" "<<B[i]<<endl;
            G[A[i]].erase(i);
            for (int x = v; x != w; ) {
// cerr<<"  cycle "<<x<<endl;
              const int j = prei[x];
              prei[x] = -1;
              G[A[j]].erase(j);
              x = A[j];
            }
            v = w;
          } else {
            prei[w] = i;
            v = w;
          }
        }
      }
    }
    
    printf("%d %d\n", N, (int)ans.size());
    for (const int i : ans) {
      printf("%d %d\n", A[i] + 1, B[i] + 1);
    }
cerr<<"========"<<endl;
  }
  return 0;
}
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