test/GRL6A_1.test.cpp

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• category: test
• View this file on GitHub
  • Last commit date: 2020-03-01 12:39:31+09:00
• see: https://onlinejudge.u-aizu.ac.jp/courses/library/5/GRL/6/GRL_6_A

Depends on

• graph/ford_fulkerson.cpp
• memo/macro.hpp

Code

#define PROBLEM "https://onlinejudge.u-aizu.ac.jp/courses/library/5/GRL/6/GRL_6_A"
#include "../memo/macro.hpp"
#include "../graph/ford_fulkerson.cpp"

signed main(void) {
    ll v, e;
    cin >> v >> e;
    FordFulkerson flow(v);
    REP(i, e) {
        ll u, v, c;
        cin >> u >> v >> c;
        flow.add_edge(u, v, c);
    }

    cout << flow.max_flow(0, v-1) << endl;

    return 0;
}

#line 1 "test/GRL6A_1.test.cpp"
#define PROBLEM "https://onlinejudge.u-aizu.ac.jp/courses/library/5/GRL/6/GRL_6_A"
#line 1 "memo/macro.hpp"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using PII = pair<ll, ll>;
#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()
template<typename T> void chmin(T &a, const T &b) { a = min(a, b); }
template<typename T> void chmax(T &a, const T &b) { a = max(a, b); }
struct FastIO {FastIO() { cin.tie(0); ios::sync_with_stdio(0); }}fastiofastio;
const ll INF = 1LL<<60;
#line 1 "graph/ford_fulkerson.cpp"
// BEGIN CUT
struct FordFulkerson {
    struct edge {
        int to;
        ll cap;
        int rev;
        bool isrev;
    };

    vector<vector<edge>> g;
    vector<int> used;
    int timestamp;

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

    FordFulkerson() {}
    FordFulkerson(int n) : timestamp(0), g(n), used(n, -1) {}

    void add_edge(int from, int to, ll cap) {
        g[from].emplace_back((edge){to, cap, (int)g[to].size(), false});
        g[to].emplace_back((edge){from, 0, (int)g[from].size()-1, true});
    }

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

    friend ostream &operator <<(ostream& out, const FordFulkerson& a){
        out << "-----" << endl;
        for(int i = 0; i < (int)a.g.size(); i++) {
            for(auto &e : a.g[i]) {
                if(e.isrev) continue;
                auto &rev_e = a.g[e.to][e.rev];
                out << i << "->" << e.to << " (flow: " << rev_e.cap << "/" << e.cap + rev_e.cap << ")" << endl;
            }
        }
        out << "-----" << endl;
        return out;
    }
};
// END CUT
#line 4 "test/GRL6A_1.test.cpp"

signed main(void) {
    ll v, e;
    cin >> v >> e;
    FordFulkerson flow(v);
    REP(i, e) {
        ll u, v, c;
        cin >> u >> v >> c;
        flow.add_edge(u, v, c);
    }

    cout << flow.max_flow(0, v-1) << endl;

    return 0;
}

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