library
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verify/aoj-max_flow.test.cpp
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- Last update: 2023-09-23 21:29:16+09:00
- Problem: http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=GRL_6_A
Depends on
Code
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=GRL_6_A"
#include "library/template/template.cpp"
// library
#include "library/graph/flow/max_flow.cpp"
int main() {
int V, E;
cin >> V >> E;
mf_graph<ll> mf(V);
rep(i, E) {
int u, v, c;
cin >> u >> v >> c;
mf.add_edge(u, v, c);
}
print(mf.flow(0, V - 1));
}#line 1 "verify/aoj-max_flow.test.cpp"
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=GRL_6_A"
#line 2 "library/template/template.cpp"
/* #region header */
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
// types
using ll = long long;
using ull = unsigned long long;
using ld = long double;
typedef pair<ll, ll> Pl;
typedef pair<int, int> Pi;
typedef vector<ll> vl;
typedef vector<int> vi;
typedef vector<char> vc;
template <typename T>
using mat = vector<vector<T>>;
typedef vector<vector<int>> vvi;
typedef vector<vector<long long>> vvl;
typedef vector<vector<char>> vvc;
// abreviations
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define rep_(i, a_, b_, a, b, ...) for (ll i = (a), max_i = (b); i < max_i; i++)
#define rep(i, ...) rep_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
#define rrep_(i, a_, b_, a, b, ...) \
for (ll i = (b - 1), min_i = (a); i >= min_i; i--)
#define rrep(i, ...) rrep_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
#define srep(i, a, b, c) for (ll i = (a), max_i = (b); i < max_i; i += c)
#define SZ(x) ((int)(x).size())
#define pb(x) push_back(x)
#define eb(x) emplace_back(x)
#define mp make_pair
//入出力
#define print(x) cout << x << endl
template <class T>
ostream &operator<<(ostream &os, const vector<T> &v)
{
for (auto &e : v)
cout << e << " ";
cout << endl;
return os;
}
void scan(int &a) { cin >> a; }
void scan(long long &a) { cin >> a; }
void scan(char &a) { cin >> a; }
void scan(double &a) { cin >> a; }
void scan(string &a) { cin >> a; }
template <class T>
void scan(vector<T> &a)
{
for (auto &i : a)
scan(i);
}
#define vsum(x) accumulate(all(x), 0LL)
#define vmax(a) *max_element(all(a))
#define vmin(a) *min_element(all(a))
#define lb(c, x) distance((c).begin(), lower_bound(all(c), (x)))
#define ub(c, x) distance((c).begin(), upper_bound(all(c), (x)))
// functions
// gcd(0, x) fails.
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
template <class T>
bool chmax(T &a, const T &b)
{
if (a < b)
{
a = b;
return 1;
}
return 0;
}
template <class T>
bool chmin(T &a, const T &b)
{
if (b < a)
{
a = b;
return 1;
}
return 0;
}
template <typename T>
T mypow(T x, ll n)
{
T ret = 1;
while (n > 0)
{
if (n & 1)
(ret *= x);
(x *= x);
n >>= 1;
}
return ret;
}
ll modpow(ll x, ll n, const ll mod)
{
ll ret = 1;
while (n > 0)
{
if (n & 1)
(ret *= x);
(x *= x);
n >>= 1;
x %= mod;
ret %= mod;
}
return ret;
}
ll safemod(ll x, ll mod) { return (x % mod + mod) % mod; }
int popcnt(ull x) { return __builtin_popcountll(x); }
template <typename T>
vector<int> IOTA(vector<T> a)
{
int n = a.size();
vector<int> id(n);
iota(all(id), 0);
sort(all(id), [&](int i, int j)
{ return a[i] < a[j]; });
return id;
}
long long xor64(long long range) {
static uint64_t x = 88172645463325252ULL;
x ^= x << 13;
x ^= x >> 7;
return (x ^= x << 17) % range;
}
struct Timer
{
clock_t start_time;
void start() { start_time = clock(); }
int lap()
{
// return x ms.
return (clock() - start_time) * 1000 / CLOCKS_PER_SEC;
}
};
template <typename T = int>
struct Edge
{
int from, to;
T cost;
int idx;
Edge() = default;
Edge(int from, int to, T cost = 1, int idx = -1)
: from(from), to(to), cost(cost), idx(idx) {}
operator int() const { return to; }
};
template <typename T = int>
struct Graph
{
vector<vector<Edge<T>>> g;
int es;
Graph() = default;
explicit Graph(int n) : g(n), es(0) {}
size_t size() const { return g.size(); }
void add_directed_edge(int from, int to, T cost = 1)
{
g[from].emplace_back(from, to, cost, es++);
}
void add_edge(int from, int to, T cost = 1)
{
g[from].emplace_back(from, to, cost, es);
g[to].emplace_back(to, from, cost, es++);
}
void read(int M, int padding = -1, bool weighted = false,
bool directed = false)
{
for (int i = 0; i < M; i++)
{
int a, b;
cin >> a >> b;
a += padding;
b += padding;
T c = T(1);
if (weighted)
cin >> c;
if (directed)
add_directed_edge(a, b, c);
else
add_edge(a, b, c);
}
}
};
/* #endregion*/
// constant
#define inf 1000000000ll
#define INF 4000000004000000000LL
#define endl '\n'
const long double eps = 0.000000000000001;
const long double PI = 3.141592653589793;
#line 4 "verify/aoj-max_flow.test.cpp"
// library
#line 1 "library/graph/flow/max_flow.cpp"
/**
* @brief 最大流
* @docs docs/max_flow.md
*/
template <class Cap>
struct mf_graph {
public:
mf_graph() : _n(0) {
}
explicit mf_graph(int n) : _n(n), g(n) {
}
int add_edge(int from, int to, Cap cap) {
assert(0 <= from && from < _n);
assert(0 <= to && to < _n);
assert(0 <= cap);
int m = int(pos.size());
pos.push_back({from, int(g[from].size())});
int from_id = int(g[from].size());
int to_id = int(g[to].size());
if (from == to) to_id++;
g[from].push_back(_edge{to, to_id, cap});
g[to].push_back(_edge{from, from_id, 0});
return m;
}
struct edge {
int from, to;
Cap cap, flow;
};
edge get_edge(int i) {
int m = int(pos.size());
assert(0 <= i && i < m);
auto _e = g[pos[i].first][pos[i].second];
auto _re = g[_e.to][_e.rev];
return edge{pos[i].first, _e.to, _e.cap + _re.cap, _re.cap};
}
std::vector<edge> edges() {
int m = int(pos.size());
std::vector<edge> result;
for (int i = 0; i < m; i++) {
result.push_back(get_edge(i));
}
return result;
}
void change_edge(int i, Cap new_cap, Cap new_flow) {
int m = int(pos.size());
assert(0 <= i && i < m);
assert(0 <= new_flow && new_flow <= new_cap);
auto &_e = g[pos[i].first][pos[i].second];
auto &_re = g[_e.to][_e.rev];
_e.cap = new_cap - new_flow;
_re.cap = new_flow;
}
Cap flow(int s, int t) {
return flow(s, t, std::numeric_limits<Cap>::max());
}
Cap flow(int s, int t, Cap flow_limit) {
assert(0 <= s && s < _n);
assert(0 <= t && t < _n);
assert(s != t);
std::vector<int> level(_n), iter(_n);
deque<int> que;
auto bfs = [&]() {
std::fill(level.begin(), level.end(), -1);
level[s] = 0;
que.clear();
que.push_front(s);
while (!que.empty()) {
int v = que.front();
que.pop_front();
for (auto e : g[v]) {
if (e.cap == 0 || level[e.to] >= 0) continue;
level[e.to] = level[v] + 1;
if (e.to == t) return;
que.push_front(e.to);
}
}
};
auto dfs = [&](auto self, int v, Cap up) {
if (v == s) return up;
Cap res = 0;
int level_v = level[v];
for (int &i = iter[v]; i < int(g[v].size()); i++) {
_edge &e = g[v][i];
if (level_v <= level[e.to] || g[e.to][e.rev].cap == 0) continue;
Cap d = self(self, e.to, std::min(up - res, g[e.to][e.rev].cap));
if (d <= 0) continue;
g[v][i].cap += d;
g[e.to][e.rev].cap -= d;
res += d;
if (res == up) return res;
}
level[v] = _n;
return res;
};
Cap flow = 0;
while (flow < flow_limit) {
bfs();
if (level[t] == -1) break;
std::fill(iter.begin(), iter.end(), 0);
Cap f = dfs(dfs, t, flow_limit - flow);
if (!f) break;
flow += f;
}
return flow;
}
std::vector<bool> min_cut(int s) {
std::vector<bool> visited(_n);
deque<int> que;
que.push_front(s);
while (!que.empty()) {
int p = que.front();
que.pop_front();
visited[p] = true;
for (auto e : g[p]) {
if (e.cap && !visited[e.to]) {
visited[e.to] = true;
que.push_front(e.to);
}
}
}
return visited;
}
private:
int _n;
struct _edge {
int to, rev;
Cap cap;
};
std::vector<std::pair<int, int>> pos;
std::vector<std::vector<_edge>> g;
};
#line 6 "verify/aoj-max_flow.test.cpp"
int main() {
int V, E;
cin >> V >> E;
mf_graph<ll> mf(V);
rep(i, E) {
int u, v, c;
cin >> u >> v >> c;
mf.add_edge(u, v, c);
}
print(mf.flow(0, V - 1));
}