結果

問題 No.2464 To DAG
ユーザー 👑 hos.lyrichos.lyric
提出日時 2023-09-08 22:31:38
言語 C++14
(gcc 12.3.0 + boost 1.83.0)
結果
WA  
実行時間 -
コード長 8,376 bytes
コンパイル時間 1,396 ms
コンパイル使用メモリ 121,688 KB
実行使用メモリ 87,716 KB
最終ジャッジ日時 2024-06-26 15:44:19
合計ジャッジ時間 15,942 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge5
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
5,248 KB
testcase_01 WA -
testcase_02 AC 363 ms
87,716 KB
testcase_03 WA -
testcase_04 WA -
testcase_05 WA -
testcase_06 WA -
testcase_07 WA -
testcase_08 WA -
testcase_09 WA -
testcase_10 WA -
testcase_11 WA -
testcase_12 WA -
testcase_13 WA -
testcase_14 AC 163 ms
33,080 KB
testcase_15 AC 237 ms
41,344 KB
testcase_16 AC 110 ms
24,320 KB
testcase_17 AC 17 ms
6,784 KB
testcase_18 AC 68 ms
16,768 KB
testcase_19 AC 2 ms
5,376 KB
testcase_20 AC 2 ms
5,376 KB
testcase_21 AC 1 ms
5,376 KB
testcase_22 WA -
testcase_23 WA -
testcase_24 WA -
testcase_25 WA -
testcase_26 AC 40 ms
12,672 KB
testcase_27 AC 264 ms
50,104 KB
testcase_28 AC 266 ms
50,220 KB
testcase_29 AC 257 ms
49,448 KB
testcase_30 AC 140 ms
19,840 KB
testcase_31 AC 126 ms
14,208 KB
testcase_32 AC 114 ms
12,288 KB
testcase_33 WA -
testcase_34 WA -
testcase_35 WA -
testcase_36 WA -
testcase_37 WA -
testcase_38 WA -
testcase_39 AC 43 ms
39,780 KB
testcase_40 AC 41 ms
39,784 KB
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")


struct HLD {
  int n, rt;
  // needs to be tree
  // vertex lists
  // modified in build(rt) (parent removed, heavy child first)
  vector<vector<int>> graph;
  vector<int> sz, par, dep;
  int zeit;
  vector<int> dis, fin, sid;
  // head vertex (minimum depth) in heavy path
  vector<int> head;

  HLD() : n(0), rt(-1), zeit(0) {}
  explicit HLD(int n_) : n(n_), rt(-1), graph(n), zeit(0) {}
  void ae(int u, int v) {
    assert(0 <= u); assert(u < n);
    assert(0 <= v); assert(v < n);
    graph[u].push_back(v);
    graph[v].push_back(u);
  }

  void dfsSz(int u) {
    sz[u] = 1;
    for (const int v : graph[u]) {
      auto it = std::find(graph[v].begin(), graph[v].end(), u);
      if (it != graph[v].end()) graph[v].erase(it);
      par[v] = u;
      dep[v] = dep[u] + 1;
      dfsSz(v);
      sz[u] += sz[v];
    }
  }
  void dfsHLD(int u) {
    dis[u] = zeit++;
    const int deg = graph[u].size();
    if (deg > 0) {
      int vm = graph[u][0];
      int jm = 0;
      for (int j = 1; j < deg; ++j) {
        const int v = graph[u][j];
        if (sz[vm] < sz[v]) {
          vm = v;
          jm = j;
        }
      }
      swap(graph[u][0], graph[u][jm]);
      head[vm] = head[u];
      dfsHLD(vm);
      for (int j = 1; j < deg; ++j) {
        const int v = graph[u][j];
        head[v] = v;
        dfsHLD(v);
      }
    }
    fin[u] = zeit;
  }
  void build(int rt_) {
    assert(0 <= rt_); assert(rt_ < n);
    rt = rt_;
    sz.assign(n, 0);
    par.assign(n, -1);
    dep.assign(n, -1);
    dep[rt] = 0;
    dfsSz(rt);
    zeit = 0;
    dis.assign(n, -1);
    fin.assign(n, -1);
    head.assign(n, -1);
    head[rt] = rt;
    dfsHLD(rt);
    assert(zeit == n);
    sid.assign(n, -1);
    for (int u = 0; u < n; ++u) sid[dis[u]] = u;
  }

  friend ostream &operator<<(ostream &os, const HLD &hld) {
    const int maxDep = *max_element(hld.dep.begin(), hld.dep.end());
    vector<string> ss(2 * maxDep + 1);
    int pos = 0, maxPos = 0;
    for (int j = 0; j < hld.n; ++j) {
      const int u = hld.sid[j];
      const int d = hld.dep[u];
      if (hld.head[u] == u) {
        if (j != 0) {
          pos = maxPos + 1;
          ss[2 * d - 1].resize(pos, '-');
          ss[2 * d - 1] += '+';
        }
      } else {
        ss[2 * d - 1].resize(pos, ' ');
        ss[2 * d - 1] += '|';
      }
      ss[2 * d].resize(pos, ' ');
      ss[2 * d] += std::to_string(u);
      if (maxPos < static_cast<int>(ss[2 * d].size())) {
        maxPos = ss[2 * d].size();
      }
    }
    for (int d = 0; d <= 2 * maxDep; ++d) os << ss[d] << '\n';
    return os;
  }

  bool contains(int u, int v) const {
    return (dis[u] <= dis[v] && dis[v] < fin[u]);
  }
  int lca(int u, int v) const {
    assert(0 <= u); assert(u < n);
    assert(0 <= v); assert(v < n);
    for (; head[u] != head[v]; ) (dis[u] > dis[v]) ? (u = par[head[u]]) : (v = par[head[v]]);
    return (dis[u] > dis[v]) ? v : u;
  }
  int jumpUp(int u, int d) const {
    assert(0 <= u); assert(u < n);
    assert(d >= 0);
    if (dep[u] < d) return -1;
    const int tar = dep[u] - d;
    for (u = head[u]; ; u = head[par[u]]) {
      if (dep[u] <= tar) return sid[dis[u] + (tar - dep[u])];
    }
  }
  int jump(int u, int v, int d) const {
    assert(0 <= u); assert(u < n);
    assert(0 <= v); assert(v < n);
    assert(d >= 0);
    const int l = lca(u, v);
    const int du = dep[u] - dep[l], dv = dep[v] - dep[l];
    if (d <= du) {
      return jumpUp(u, d);
    } else if (d <= du + dv) {
      return jumpUp(v, du + dv - d);
    } else {
      return -1;
    }
  }
  // [u, v) or [u, v]
  template <class F> void doPathUp(int u, int v, bool inclusive, F f) const {
    assert(contains(v, u));
    for (; head[u] != head[v]; u = par[head[u]]) f(dis[head[u]], dis[u] + 1);
    if (inclusive) {
      f(dis[v], dis[u] + 1);
    } else {
      if (v != u) f(dis[v] + 1, dis[u] + 1);
    }
  }
  // not path order, include lca(u, v) or not
  template <class F> void doPath(int u, int v, bool inclusive, F f) const {
    const int l = lca(u, v);
    doPathUp(u, l, false, f);
    doPathUp(v, l, inclusive, f);
  }

  // (vs, ps): compressed tree
  // vs: DFS order (sorted by dis)
  // vs[ps[x]]: the parent of vs[x]
  // ids[vs[x]] = x, not set for non-tree vertex
  vector<int> ids;
  pair<vector<int>, vector<int>> compress(vector<int> us) {
    // O(n) first time
    ids.resize(n, -1);
    std::sort(us.begin(), us.end(), [&](int u, int v) -> bool {
      return (dis[u] < dis[v]);
    });
    us.erase(std::unique(us.begin(), us.end()), us.end());
    int usLen = us.size();
    assert(usLen >= 1);
    for (int x = 1; x < usLen; ++x) us.push_back(lca(us[x - 1], us[x]));
    std::sort(us.begin(), us.end(), [&](int u, int v) -> bool {
      return (dis[u] < dis[v]);
    });
    us.erase(std::unique(us.begin(), us.end()), us.end());
    usLen = us.size();
    for (int x = 0; x < usLen; ++x) ids[us[x]] = x;
    vector<int> ps(usLen, -1);
    for (int x = 1; x < usLen; ++x) ps[x] = ids[lca(us[x - 1], us[x])];
    return make_pair(us, ps);
  }
};

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


template <class T> void bAdd(vector<T> &bit, int pos, const T &val) {
  const int bitN = bit.size();
  for (int x = pos; x < bitN; x |= x + 1) bit[x] += val;
}
template <class T> T bSum(const vector<T> &bit, int pos) {
  T ret = 0;
  for (int x = pos; x > 0; x &= x - 1) ret += bit[x - 1];
  return ret;
}
template <class T> T bSum(const vector<T> &bit, int pos0, int pos1) {
  return bSum(bit, pos1) - bSum(bit, pos0);
}


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

vector<vector<int>> G;
vector<int> vis, on;
vector<int> pari;

void dfs(int u) {
  vis[u] = 1;
  for (const int i : G[u]) {
    const int v = B[i];
    if (!vis[v]) {
      pari[v] = i;
      on[i] = 1;
      dfs(v);
    }
  }
}

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]].push_back(i);
    }
    vis.assign(N, 0);
    pari.assign(N, -1);
    on.assign(M, 0);
    HLD hld(N + 1);
    for (int u = 0; u < N; ++u) if (!vis[u]) {
      hld.ae(N, u);
      dfs(u);
    }
    for (int i = 0; i < M; ++i) if (on[i]) {
      hld.ae(A[i], B[i]);
    }
    hld.build(N);
// cerr<<hld<<endl;
    
    vector<int> bit(N, 0);
    vector<int> del(M, 0);
    for (int i = 0; i < M; ++i) if (!on[i]) {
      if (hld.contains(B[i], A[i])) {
// cerr<<"back "<<A[i]<<" "<<B[i]<<endl;
        int sum = 0;
        hld.doPathUp(A[i], B[i], false, [&](int x, int y) -> void {
          sum += bSum(bit, x, y);
        });
        if (sum == 0) {
          del[i] = 1;
          for (int v = A[i]; v != B[i]; v = hld.par[v]) {
            del[pari[v]] = 1;
            bAdd(bit, hld.dis[v], +1);
          }
        }
      }
    }
    
    int ansCnt = 0;
    for (int i = 0; i < M; ++i) if (!del[i]) {
      ++ansCnt;
    }
    printf("%d %d\n", N, ansCnt);
    for (int i = 0; i < M; ++i) if (!del[i]) {
      printf("%d %d\n", A[i] + 1, B[i] + 1);
    }
cerr<<"========"<<endl;
  }
  return 0;
}
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