結果
| 問題 | No.3668 Minimum Cut |
| コンテスト | |
| ユーザー |
 hitonanode
|
| 提出日時 | 2026-09-04 23:03:58 |
| 言語 | C++23 (gcc 15.3.0 + boost 1.92.0) |
| 結果 |
AC
|
| 実行時間 | 47 ms / 2,000 ms |
| + 624µs | |
| コード長 | 12,360 bytes |
| 記録 | |
| コンパイル時間 | 1,910 ms |
| コンパイル使用メモリ | 302,056 KB |
| 実行使用メモリ | 9,792 KB |
| 最終ジャッジ日時 | 2026-09-04 23:07:32 |
| 合計ジャッジ時間 | 4,459 ms |
|
ジャッジサーバーID （参考情報） |
judge5_0 / judge1_0 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| sample | AC * 3 |
| other | AC * 39 |
ソースコード
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <deque>
#include <forward_list>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <optional>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using lint = long long;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template <typename T> bool chmax(T &m, const T q) { return m < q ? (m = q, true) : false; }
template <typename T> bool chmin(T &m, const T q) { return m > q ? (m = q, true) : false; }
const std::vector<std::pair<int, int>> grid_dxs{{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
int floor_lg(long long x) { return x <= 0 ? -1 : 63 - __builtin_clzll(x); }
template <class T1, class T2> T1 floor_div(T1 num, T2 den) { return (num > 0 ? num / den : -((-num + den - 1) / den)); }
template <class T1, class T2> std::pair<T1, T2> operator+(const std::pair<T1, T2> &l, const std::pair<T1, T2> &r) { return std::make_pair(l.first + r.first, l.second + r.second); }
template <class T1, class T2> std::pair<T1, T2> operator-(const std::pair<T1, T2> &l, const std::pair<T1, T2> &r) { return std::make_pair(l.first - r.first, l.second - r.second); }
template <class T> std::vector<T> sort_unique(std::vector<T> vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; }
template <class T> int arglb(const std::vector<T> &v, const T &x) { return std::distance(v.begin(), std::lower_bound(v.begin(), v.end(), x)); }
template <class T> int argub(const std::vector<T> &v, const T &x) { return std::distance(v.begin(), std::upper_bound(v.begin(), v.end(), x)); }
template <class IStream, class T> IStream &operator>>(IStream &is, std::vector<T> &vec) { for (auto &v : vec) is >> v; return is; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::vector<T> &vec);
template <class OStream, class T, size_t sz> OStream &operator<<(OStream &os, const std::array<T, sz> &arr);
template <class OStream, class T, class TH> OStream &operator<<(OStream &os, const std::unordered_set<T, TH> &vec);
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const pair<T, U> &pa);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::deque<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::set<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::multiset<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::unordered_multiset<T> &vec);
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa);
template <class OStream, class TK, class TV> OStream &operator<<(OStream &os, const std::map<TK, TV> &mp);
template <class OStream, class TK, class TV, class TH> OStream &operator<<(OStream &os, const std::unordered_map<TK, TV, TH> &mp);
template <class OStream, class... T> OStream &operator<<(OStream &os, const std::tuple<T...> &tpl);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::vector<T> &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <class OStream, class T, size_t sz> OStream &operator<<(OStream &os, const std::array<T, sz> &arr) { os << '['; for (auto v : arr) os << v << ','; os << ']'; return os; }
template <class... T> std::istream &operator>>(std::istream &is, std::tuple<T...> &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return is; }
template <class OStream, class... T> OStream &operator<<(OStream &os, const std::tuple<T...> &tpl) { os << '('; std::apply([&os](auto &&... args) { ((os << args << ','), ...);}, tpl); return os << ')'; }
template <class OStream, class T, class TH> OStream &operator<<(OStream &os, const std::unordered_set<T, TH> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::deque<T> &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::set<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T> OStream &operator<<(OStream &os, const std::unordered_multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa) { return os << '(' << pa.first << ',' << pa.second << ')'; }
template <class OStream, class TK, class TV> OStream &operator<<(OStream &os, const std::map<TK, TV> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
template <class OStream, class TK, class TV, class TH> OStream &operator<<(OStream &os, const std::unordered_map<TK, TV, TH> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
#ifdef HITONANODE_LOCAL
const string COLOR_RESET = "\033[0m", BRIGHT_CYAN = "\033[1;36m", NORMAL_FAINT = "\033[0;2m";
#define dbg(x) std::cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << std::endl
#define dbgif(cond, x) ((cond) ? std::cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << std::endl : std::cerr)
#else
#define dbg(x) ((void)0)
#define dbgif(cond, x) ((void)0)
#endif
// https://hitonanode.github.io/cplib-cpp/flow/maxflow_pushrelabel.hpp
#include <cassert>
#include <limits>
#include <utility>
#include <vector>
// Maxflow (push-relabel, highest-label)
// Complexity: O(N^2 M^(1/2))
template <class Cap, int GlobalRelabelFreq = 5, bool UseGapRelabeling = true>
struct mf_pushrelabel {
struct pque_ {
std::vector<std::pair<int, int>> even_, odd_;
int se, so;
void init(int n) { even_.resize(n), odd_.resize(n), se = so = 0; };
void clear() { se = so = 0; }
bool empty() const { return se + so == 0; }
void push(int i, int h) { (h & 1 ? odd_[so++] : even_[se++]) = {i, h}; }
int highest() const {
int a = se ? even_[se - 1].second : -1, b = so ? odd_[so - 1].second : -1;
return a > b ? a : b;
}
int pop() {
if (!se or (so and odd_[so - 1].second > even_[se - 1].second))
return odd_[--so].first;
return even_[--se].first;
}
} pque;
int _n;
struct _edge {
int to, rev;
Cap cap;
};
std::vector<std::vector<_edge>> g;
std::vector<std::pair<int, int>> pos;
mf_pushrelabel(int n) : _n(n), g(n) {
static_assert(GlobalRelabelFreq >= 0, "Global relabel parameter must be nonnegative.");
}
int add_edge(int from, int to, Cap cap) {
assert(0 <= from and from < _n);
assert(0 <= to and to < _n);
assert(0 <= cap);
int m = int(pos.size());
pos.emplace_back(from, int(g[from].size()));
int from_id = g[from].size(), to_id = g[to].size() + (from == to);
g[from].push_back({to, to_id, cap});
g[to].push_back({from, from_id, Cap(0)});
return m;
}
struct edge {
int from, to;
Cap cap, flow;
};
edge get_edge(int i) const {
int m = int(pos.size());
assert(0 <= i and i < m);
auto e = g[pos[i].first][pos[i].second], re = g[e.to][e.rev];
return edge{pos[i].first, e.to, e.cap + re.cap, re.cap};
}
std::vector<edge> edges() const {
std::vector<edge> ret(pos.size());
for (int i = 0; i < int(pos.size()); i++) ret[i] = get_edge(i);
return ret;
}
std::vector<int> dist;
std::vector<int> dcnt;
std::vector<Cap> excess;
int gap;
void global_relabeling(int t) {
dist.assign(_n, _n), dist[t] = 0;
static std::vector<int> q;
if (q.empty()) q.resize(_n);
q[0] = t;
int qb = 0, qe = 1;
pque.clear();
if (UseGapRelabeling) gap = 1, dcnt.assign(_n + 1, 0);
while (qb < qe) {
int now = q[qb++];
if (UseGapRelabeling) gap = dist[now] + 1, dcnt[dist[now]]++;
if (excess[now] > 0) pque.push(now, dist[now]);
for (const auto &e : g[now]) {
if (g[e.to][e.rev].cap and dist[e.to] == _n) {
dist[e.to] = dist[now] + 1;
while (int(q.size()) <= qe) q.push_back(0);
q[qe++] = e.to;
}
}
}
}
Cap flow(int s, int t) { return flow(s, t, std::numeric_limits<Cap>::max(), true); }
Cap flow(int s, int t, Cap flow_limit, bool retrieve = true) {
assert(0 <= s and s < _n);
assert(0 <= t and t < _n);
assert(s != t);
excess.resize(_n, 0);
excess[s] += flow_limit, excess[t] -= flow_limit;
dist.assign(_n, 0);
dist[s] = _n;
if (UseGapRelabeling) gap = 1, dcnt.assign(_n + 1, 0), dcnt[0] = _n - 1;
pque.init(_n);
for (auto &e : g[s]) _push(s, e);
_run(t);
Cap ret = excess[t] + flow_limit;
excess[s] += excess[t], excess[t] = 0;
if (retrieve) {
global_relabeling(s);
_run(s);
assert(excess == std::vector<Cap>(_n, 0));
}
return ret;
}
void _run(int t) {
if (GlobalRelabelFreq) global_relabeling(t);
int tick = pos.size() * GlobalRelabelFreq;
while (!pque.empty()) {
int i = pque.pop();
if (UseGapRelabeling and dist[i] > gap) continue;
int dnxt = _n * 2 - 1;
for (auto &e : g[i]) {
if (!e.cap) continue;
if (dist[e.to] == dist[i] - 1) {
_push(i, e);
if (excess[i] == 0) break;
} else {
if (dist[e.to] + 1 < dnxt) dnxt = dist[e.to] + 1;
}
}
if (excess[i] > 0) {
if (UseGapRelabeling) {
if (dnxt != dist[i] and dcnt[dist[i]] == 1 and dist[i] < gap) gap = dist[i];
if (dnxt == gap) gap++;
while (pque.highest() > gap) pque.pop();
if (dnxt > gap) dnxt = _n;
if (dist[i] != dnxt) dcnt[dist[i]]--, dcnt[dnxt]++;
}
dist[i] = dnxt;
if (!UseGapRelabeling or dist[i] < gap) pque.push(i, dist[i]);
}
if (GlobalRelabelFreq and --tick == 0) {
tick = pos.size() * GlobalRelabelFreq, global_relabeling(t);
}
}
return;
}
void _push(int i, _edge &e) {
Cap delta = e.cap < excess[i] ? e.cap : excess[i];
excess[i] -= delta, e.cap -= delta;
excess[e.to] += delta, g[e.to][e.rev].cap += delta;
if (excess[e.to] > 0 and excess[e.to] <= delta) {
if (!UseGapRelabeling or dist[e.to] <= gap) pque.push(e.to, dist[e.to]);
}
}
};
int main() {
int N, M, S, T;
cin >> N >> M >> S >> T;
mf_pushrelabel<lint> mf(N);
REP(_, M) {
int u, v, c;
cin >> u >> v >> c;
--u, --v;
mf.add_edge(u, v, c);
}
--S, --T;
cout << mf.flow(S, T) << '\n';
}