tests/Dominator_Tree.test.cpp

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Last update: 2025-11-28 02:09:51+07:00
Problem: https://judge.yosupo.jp/problem/dominatortree

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Code

#define PROBLEM "https://judge.yosupo.jp/problem/dominatortree"

#include "../misc/macros.h"
#include "../graph/Dominator.h"

void solve() {
  int n, m, s;
  cin >> n >> m >> s;
  vector<vi> g(n);
  for (int i = 0; i < m; ++i) {
    int u, v;
    cin >> u >> v;
    g[u].pb(v);
  }
  auto tree = DomTree(g, s);
  tree[s] = s;
  for (int i = 0; i < n; ++i) cout << tree[i] << ' ';
}

int main() {
  cin.tie(0)->sync_with_stdio(0);
  cin.exceptions(cin.failbit);
  int tc = 1;
  // cin >> tc;
  for (int i = 1; i <= tc; ++i) {
    solve();
  }
}

#line 1 "tests/Dominator_Tree.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/dominatortree"

#line 1 "misc/macros.h"
// #pragma GCC optimize("Ofast,unroll-loops")       // unroll long, simple loops
// #pragma GCC target("avx2,fma")                   // vectorizing code
// #pragma GCC target("lzcnt,popcnt,abm,bmi,bmi2")  // for fast bitset operation

#include <bits/extc++.h>
#include <tr2/dynamic_bitset>

using namespace std;
using namespace __gnu_pbds;  // ordered_set, gp_hash_table
// using namespace __gnu_cxx; // rope

// for templates to work
#define all(x) (x).begin(), (x).end()
#define sz(x) (int) (x).size()
#define pb push_back
#define eb emplace_back
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
using i128 = __int128_t;
using u128 = __uint128_t;
using ld = long double;
using pii = pair<i32, i32>;
using vi = vector<i32>;

// fast map
const int RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();
struct chash {  // customize hash function for gp_hash_table
  int operator()(int x) const { return x ^ RANDOM; }
};
gp_hash_table<int, int, chash> table;

/* ordered set
    find_by_order(k): returns an iterator to the k-th element (0-based)
    order_of_key(k): returns the number of elements in the set that are strictly less than k
*/
template <class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

/*  rope
    rope <int> cur = v.substr(l, r - l + 1);
    v.erase(l, r - l + 1);
    v.insert(v.mutable_begin(), cur);
*/
#line 1 "graph/Dominator.h"
vector<int> DomTree(const vector<vi>& g, int s) {
  int n = sz(g), t = 0;
  vector<int> arr(n, -1), rev(n), par(n), sdom(n), dom(n), dsu(n), lab(n), res(n, -1);
  vector<vi> rg(n), buck(n);
  auto dfs = [&](auto&& self, int u) -> void {
    arr[u] = t, rev[t] = u, lab[t] = sdom[t] = dsu[t] = t, t++;
    for (int v : g[u]) {
      if (arr[v] == -1) self(self, v), par[arr[v]] = arr[u];
      rg[arr[v]].pb(arr[u]);
    }
  };
  dfs(dfs, s);
  auto find = [&](auto&& self, int u) -> int {
    if (u == dsu[u]) return u;
    int v = self(self, dsu[u]);
    if (sdom[lab[dsu[u]]] < sdom[lab[u]]) lab[u] = lab[dsu[u]];
    return dsu[u] = v;
  };
  for (int i = t - 1; i; --i) {
    for (int v : rg[i]) find(find, v), sdom[i] = min(sdom[i], sdom[lab[v]]);
    buck[sdom[i]].pb(i);
    int p = par[i]; dsu[i] = p;
    for (int v : buck[p]) find(find, v), dom[v] = (sdom[lab[v]] == sdom[v] ? p : lab[v]);
    buck[p].clear();
  }
  for (int i = 1; i < t; ++i) {
    if (dom[i] != sdom[i]) dom[i] = dom[dom[i]];
    res[rev[i]] = rev[dom[i]];
  }
  return res;
}
#line 5 "tests/Dominator_Tree.test.cpp"

void solve() {
  int n, m, s;
  cin >> n >> m >> s;
  vector<vi> g(n);
  for (int i = 0; i < m; ++i) {
    int u, v;
    cin >> u >> v;
    g[u].pb(v);
  }
  auto tree = DomTree(g, s);
  tree[s] = s;
  for (int i = 0; i < n; ++i) cout << tree[i] << ' ';
}

int main() {
  cin.tie(0)->sync_with_stdio(0);
  cin.exceptions(cin.failbit);
  int tc = 1;
  // cin >> tc;
  for (int i = 1; i <= tc; ++i) {
    solve();
  }
}