verify/AizuOnlineJudge/graph/flow/GRL_6_A_2.test.cpp

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• Last update: 2026-05-03 20:10:43+09:00
• Problem: https://onlinejudge.u-aizu.ac.jp/problems/GRL_6_A

Depends on

• Maxflow (Dinic法) (academic/MaxflowDinic.hpp)
• Template (template/template.hpp)

Code

#include "../../../../template/template.hpp"
#define PROBLEM "https://onlinejudge.u-aizu.ac.jp/problems/GRL_6_A"
#include "../../../../academic/MaxflowDinic.hpp"

int main() {
  cin.tie(0)->sync_with_stdio(0);
  int v, e;
  in(v, e);
  max_flow<int> g(v);
  rep(i, e) {
    int u, v, c;
    in(u, v, c);
    g.add_edge(u, v, c);
  }
  out(g.flow(0, v - 1));
}

#line 2 "template/template.hpp"
#pragma region Macros
#include <bits/stdc++.h>
#include <tr2/dynamic_bitset>

using namespace std;
using namespace tr2;
using lint = long long;
using ull = unsigned long long;
using ld = long double;
using int128 = __int128_t;
#define all(x) (x).begin(), (x).end()
#define uniqv(v) v.erase(unique(all(v)), v.end())
#define OVERLOAD_REP(_1, _2, _3, name, ...) name
#define REP1(i, n) for (auto i = std::decay_t<decltype(n)>{}; (i) != (n); ++(i))
#define REP2(i, l, r) for (auto i = (l); (i) != (r); ++(i))
#define rep(...) OVERLOAD_REP(__VA_ARGS__, REP2, REP1)(__VA_ARGS__)
#define logfixed(x) cout << fixed << setprecision(10) << x << endl;

ostream &operator<<(ostream &dest, __int128_t value) {
  ostream::sentry s(dest);
  if (s) {
    __uint128_t tmp = value < 0 ? -value : value;
    char buffer[128];
    char *d = end(buffer);
    do {
      --d;
      *d = "0123456789"[tmp % 10];
      tmp /= 10;
    } while (tmp != 0);
    if (value < 0) {
      --d;
      *d = '-';
    }
    int len = end(buffer) - d;
    if (dest.rdbuf()->sputn(d, len) != len) {
      dest.setstate(ios_base::badbit);
    }
  }
  return dest;
}

template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << (i + 1 != (int)v.size() ? " " : "");
  }
  return os;
}

template <typename T>
ostream &operator<<(ostream &os, const set<T> &set_var) {
  for (auto itr = set_var.begin(); itr != set_var.end(); itr++) {
    os << *itr;
    ++itr;
    if (itr != set_var.end()) os << " ";
    itr--;
  }
  return os;
}

template <typename T>
ostream &operator<<(ostream &os, const unordered_set<T> &set_var) {
  for (auto itr = set_var.begin(); itr != set_var.end(); itr++) {
    os << *itr;
    ++itr;
    if (itr != set_var.end()) os << " ";
    itr--;
  }
  return os;
}

template <typename T, typename U>
ostream &operator<<(ostream &os, const map<T, U> &map_var) {
  for (auto itr = map_var.begin(); itr != map_var.end(); itr++) {
    os << itr->first << " -> " << itr->second << "\n";
  }
  return os;
}

template <typename T, typename U>
ostream &operator<<(ostream &os, const unordered_map<T, U> &map_var) {
  for (auto itr = map_var.begin(); itr != map_var.end(); itr++) {
    os << itr->first << " -> " << itr->second << "\n";
  }
  return os;
}

template <typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &pair_var) {
  os << pair_var.first << " " << pair_var.second;
  return os;
}

void out() { cout << '\n'; }
template <class T, class... Ts>
void out(const T &a, const Ts &...b) {
  cout << a;
  (cout << ... << (cout << ' ', b));
  cout << '\n';
}

void outf() { cout << '\n'; }
template <class T, class... Ts>
void outf(const T &a, const Ts &...b) {
  cout << fixed << setprecision(14) << a;
  (cout << ... << (cout << ' ', b));
  cout << '\n';
}

template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
  for (T &in : v) is >> in;
  return is;
}

inline void in(void) { return; }
template <typename First, typename... Rest>
void in(First &first, Rest &...rest) {
  cin >> first;
  in(rest...);
  return;
}

template <typename T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T>
bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}

vector<lint> dx8 = {1, 1, 0, -1, -1, -1, 0, 1};
vector<lint> dy8 = {0, 1, 1, 1, 0, -1, -1, -1};
vector<lint> dx4 = {1, 0, -1, 0};
vector<lint> dy4 = {0, 1, 0, -1};

#pragma endregion
#line 2 "verify/AizuOnlineJudge/graph/flow/GRL_6_A_2.test.cpp"
#define PROBLEM "https://onlinejudge.u-aizu.ac.jp/problems/GRL_6_A"
#line 1 "academic/MaxflowDinic.hpp"
template <class Cap>
class max_flow {
 private:
  struct Edge {
    int from, to;
    Cap cap, flow;
    int rev;
  };

  vector<pair<int, int>> edge_id;
  vector<vector<Edge>> g;
  int n;

 public:
  max_flow(int n) : n(n) {
    g.resize(n);
  }

  void add_edge(int from, int to, Cap cap) {
    assert(from != to);
    int from_id = int(g[from].size());
    int to_id = int(g[to].size());
    edge_id.emplace_back(from, from_id);
    g[from].push_back({from, to, cap, 0, to_id});
    g[to].push_back({to, from, cap, cap, from_id});
  }

  const Edge& get_edge(int id) {
    auto [vid, eid] = edge_id[id];
    return g[vid][eid];
  }

  Cap flow(int s, int t) {
    Cap res = 0;
    vector<int> iter(n, -1);
    vector<int> dist(n, -1);

    auto bfs = [&](int s) -> void {
      fill(dist.begin(), dist.end(), -1);
      queue<int> q;
      dist[s] = 0;
      q.push(s);
      while (!q.empty()) {
        int cur = q.front();
        q.pop();
        for (int i = 0; i < int(g[cur].size()); i++) {
          Edge& edge = g[cur][i];
          if (edge.cap - edge.flow <= 0 or dist[edge.to] != -1) continue;
          dist[edge.to] = dist[cur] + 1;
          q.push(edge.to);
        }
      }
    };

    auto dfs = [&](auto& self, int cur, Cap epsilon) -> Cap {
      if (cur == t) return epsilon;
      for (int& i = iter[cur]; i < int(g[cur].size()); i++) {
        Edge& edge = g[cur][i];
        if (edge.cap - edge.flow <= 0 or dist[cur] >= dist[edge.to]) continue;
        Cap d = self(self, edge.to, min(epsilon, edge.cap - edge.flow));
        if (d > 0) {
          edge.flow += d;
          g[edge.to][edge.rev].flow -= d;
          return d;
        }
      }
      return 0;
    };

    while (1) {
      bfs(s);
      if (dist[t] < 0) break;
      fill(iter.begin(), iter.end(), 0);
      Cap f;
      while (f = dfs(dfs, s, numeric_limits<Cap>::max())) res += f;
    }

    return res;
  }

  vector<bool> min_cut(int s) {
    vector<bool> reachable(n, false);
    auto dfs = [&](auto& self, int cur) -> void {
      reachable[cur] = true;
      for (int i = 0; i < int(g[cur].size()); i++) {
        const Edge& edge = g[cur][i];
        if (edge.cap - edge.flow <= 0 or reachable[edge.to]) continue;
        self(self, edge.to);
      }
    };
    dfs(dfs, s);
    return reachable;
  }
};
#line 4 "verify/AizuOnlineJudge/graph/flow/GRL_6_A_2.test.cpp"

int main() {
  cin.tie(0)->sync_with_stdio(0);
  int v, e;
  in(v, e);
  max_flow<int> g(v);
  rep(i, e) {
    int u, v, c;
    in(u, v, c);
    g.add_edge(u, v, c);
  }
  out(g.flow(0, v - 1));
}

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