Luzhiled's Library

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:heavy_check_mark: test/verify/aoj-grl-6-a-2.test.cpp

Depends on

Code

#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=GRL_6_A"

#include "../../template/template.hpp"

#include "../../graph/flow/ford-fulkerson.hpp"

int main() {
  int V, E;
  scanf("%d %d", &V, &E);
  FordFulkerson< int > g(V);
  for(int i = 0; i < E; i++) {
    int a, b, c;
    scanf("%d %d %d", &a, &b, &c);
    g.add_edge(a, b, c);
  }
  printf("%d\n", g.max_flow(0, V - 1));
}
#line 1 "test/verify/aoj-grl-6-a-2.test.cpp"
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=GRL_6_A"

#line 1 "template/template.hpp"
#include<bits/stdc++.h>

using namespace std;

using int64 = long long;
const int mod = 1e9 + 7;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;

template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 >& p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

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 != v.size() ? " " : "");
  }
  return os;
}

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

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  explicit FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};
 
template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}
#line 4 "test/verify/aoj-grl-6-a-2.test.cpp"

#line 1 "graph/flow/ford-fulkerson.hpp"
/**
 * @brief Ford Fulkerson(最大流)
 * @docs docs/ford-fulkerson.md
 */
template< typename flow_t >
struct FordFulkerson {
  struct edge {
    int to;
    flow_t cap;
    int rev;
    bool isrev;
    int idx;
  };

  const flow_t INF;
  vector< vector< edge > > graph;
  vector< int > used;
  int timestamp;

  explicit FordFulkerson(int V) : INF(numeric_limits< flow_t >::max()), graph(V), used(V, -1), timestamp(0) {}

  void add_edge(int from, int to, flow_t cap, int idx = -1) {
    graph[from].emplace_back((edge) {to, cap, (int) graph[to].size(), false, idx});
    graph[to].emplace_back((edge) {from, 0, (int) graph[from].size() - 1, true, idx});
  }

  flow_t find_augment_path(int idx, const int t, flow_t flow) {
    if(idx == t) return flow;
    used[idx] = timestamp;
    for(auto &e : graph[idx]) {
      if(e.cap > 0 && used[e.to] != timestamp) {
        flow_t d = find_augment_path(e.to, t, min(flow, e.cap));
        if(d > 0) {
          e.cap -= d;
          graph[e.to][e.rev].cap += d;
          return d;
        }
      }
    }
    return 0;
  }

  flow_t max_flow(int s, int t) {
    flow_t flow = 0;
    for(flow_t f; (f = find_augment_path(s, t, INF)) > 0; timestamp++) {
      flow += f;
    }
    timestamp++;
    return flow;
  }

  void output() {
    for(int i = 0; i < graph.size(); i++) {
      for(auto &e : graph[i]) {
        if(e.isrev) continue;
        auto &rev_e = graph[e.to][e.rev];
        cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/" << e.cap + rev_e.cap << ")" << endl;
      }
    }
  }
};
#line 6 "test/verify/aoj-grl-6-a-2.test.cpp"

int main() {
  int V, E;
  scanf("%d %d", &V, &E);
  FordFulkerson< int > g(V);
  for(int i = 0; i < E; i++) {
    int a, b, c;
    scanf("%d %d %d", &a, &b, &c);
    g.add_edge(a, b, c);
  }
  printf("%d\n", g.max_flow(0, V - 1));
}
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