Submission #1295400

#	Time	Username	Problem	Language	Result	Execution time	Memory
1295400		Benq	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	395 ms	45572 KiB

commuter_pass

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <climits>
#include <cmath>
#include <complex>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <vector>
using namespace std;

using ll = long long;
using db = long double;  // or double, if TL is tight
using str = string;      // yay python!

// pairs
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
#define mp make_pair
#define f first
#define s second

#define tcT template <class T
#define tcTU tcT, class U
// ^ lol this makes everything look weird but I'll try it
tcT > using V = vector<T>;
tcT, size_t SZ > using AR = array<T, SZ>;
using vi = V<int>;
using vb = V<bool>;
using vl = V<ll>;
using vd = V<db>;
using vs = V<str>;
using vpi = V<pi>;
using vpl = V<pl>;
using vpd = V<pd>;

// vectors
#define sz(x) int(size(x))
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define sor(x) sort(all(x))
#define rsz resize
#define ins insert
#define pb push_back
#define eb emplace_back
#define ft front()
#define bk back()

#define lb lower_bound
#define ub upper_bound
tcT > int lwb(const V<T> &a, const T &b) { return int(lb(all(a), b) - bg(a)); }
tcT > int upb(const V<T> &a, const T &b) { return int(ub(all(a), b) - bg(a)); }

// loops
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); --i)
#define R0F(i, a) ROF(i, 0, a)
#define rep(a) F0R(_, a)
#define each(a, x) for (auto &a : x)

const int MOD = 998244353;  // 1e9+7;
const int MX = (int)2e5 + 5;
const ll BIG = 1e18;  // not too close to LLONG_MAX
const db PI = acos((db)-1);
const int dx[4]{1, 0, -1, 0}, dy[4]{0, 1, 0, -1};  // for every grid problem!!
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
template <class T> using pqg = priority_queue<T, vector<T>, greater<T>>;

// bitwise ops
// also see https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html
constexpr int pct(int x) { return __builtin_popcount(x); }  // # of bits set
constexpr int bits(int x) {  // assert(x >= 0); // make C++11 compatible until
	                         // USACO updates ...
	return x == 0 ? 0 : 31 - __builtin_clz(x);
}  // floor(log2(x))
constexpr int p2(int x) { return 1 << x; }
constexpr int msk2(int x) { return p2(x) - 1; }

ll cdiv(ll a, ll b) {
	return a / b + ((a ^ b) > 0 && a % b);
}  // divide a by b rounded up
ll fdiv(ll a, ll b) {
	return a / b - ((a ^ b) < 0 && a % b);
}  // divide a by b rounded down

tcT > bool ckmin(T &a, const T &b) {
	return b < a ? a = b, 1 : 0;
}  // set a = min(a,b)
tcT > bool ckmax(T &a, const T &b) {
	return a < b ? a = b, 1 : 0;
}  // set a = max(a,b)

tcTU > T fstTrue(T lo, T hi, U f) {
	++hi;
	assert(lo <= hi);  // assuming f is increasing
	while (lo < hi) {  // find first index such that f is true
		T mid = lo + (hi - lo) / 2;
		f(mid) ? hi = mid : lo = mid + 1;
	}
	return lo;
}
tcTU > T lstTrue(T lo, T hi, U f) {
	--lo;
	assert(lo <= hi);  // assuming f is decreasing
	while (lo < hi) {  // find first index such that f is true
		T mid = lo + (hi - lo + 1) / 2;
		f(mid) ? lo = mid : hi = mid - 1;
	}
	return lo;
}
tcT > void remDup(vector<T> &v) {  // sort and remove duplicates
	sort(all(v));
	v.erase(unique(all(v)), end(v));
}
tcTU > void safeErase(T &t, const U &u) {
	auto it = t.find(u);
	assert(it != end(t));
	t.erase(it);
}

inline namespace IO {
#define SFINAE(x, ...)                                                         \
	template <class, class = void> struct x : std::false_type {};              \
	template <class T> struct x<T, std::void_t<__VA_ARGS__>> : std::true_type {}

SFINAE(DefaultI, decltype(std::cin >> std::declval<T &>()));
SFINAE(DefaultO, decltype(std::cout << std::declval<T &>()));
SFINAE(IsTuple, typename std::tuple_size<T>::type);
SFINAE(Iterable, decltype(std::begin(std::declval<T>())));

template <auto &is> struct Reader {
	template <class T> void Impl(T &t) {
		if constexpr (DefaultI<T>::value) is >> t;
		else if constexpr (Iterable<T>::value) {
			for (auto &x : t) Impl(x);
		} else if constexpr (IsTuple<T>::value) {
			std::apply([this](auto &...args) { (Impl(args), ...); }, t);
		} else static_assert(IsTuple<T>::value, "No matching type for read");
	}
	template <class... Ts> void read(Ts &...ts) { ((Impl(ts)), ...); }
};

template <class... Ts> void re(Ts &...ts) { Reader<cin>{}.read(ts...); }
#define def(t, args...)                                                        \
	t args;                                                                    \
	re(args);

template <auto &os, bool debug, bool print_nd> struct Writer {
	string comma() const { return debug ? "," : ""; }
	template <class T> constexpr char Space(const T &) const {
		return print_nd && (Iterable<T>::value or IsTuple<T>::value) ? '\n'
		                                                             : ' ';
	}
	template <class T> void Impl(T const &t) const {
		if constexpr (DefaultO<T>::value) os << t;
		else if constexpr (Iterable<T>::value) {
			if (debug) os << '{';
			int i = 0;
			for (auto &&x : t)
				((i++) ? (os << comma() << Space(x), Impl(x)) : Impl(x));
			if (debug) os << '}';
		} else if constexpr (IsTuple<T>::value) {
			if (debug) os << '(';
			std::apply(
			    [this](auto const &...args) {
				    int i = 0;
				    (((i++) ? (os << comma() << " ", Impl(args)) : Impl(args)),
				     ...);
			    },
			    t);
			if (debug) os << ')';
		} else static_assert(IsTuple<T>::value, "No matching type for print");
	}
	template <class T> void ImplWrapper(T const &t) const {
		if (debug) os << "\033[0;31m";
		Impl(t);
		if (debug) os << "\033[0m";
	}
	template <class... Ts> void print(Ts const &...ts) const {
		((Impl(ts)), ...);
	}
	template <class F, class... Ts>
	void print_with_sep(const std::string &sep, F const &f,
	                    Ts const &...ts) const {
		ImplWrapper(f), ((os << sep, ImplWrapper(ts)), ...), os << '\n';
	}
	void print_with_sep(const std::string &) const { os << '\n'; }
};

template <class... Ts> void pr(Ts const &...ts) {
	Writer<cout, false, true>{}.print(ts...);
}
template <class... Ts> void ps(Ts const &...ts) {
	Writer<cout, false, true>{}.print_with_sep(" ", ts...);
}
}  // namespace IO

inline namespace Debug {
template <typename... Args> void err(Args... args) {
	Writer<cerr, true, false>{}.print_with_sep(" | ", args...);
}
template <typename... Args> void errn(Args... args) {
	Writer<cerr, true, true>{}.print_with_sep(" | ", args...);
}

void err_prefix(str func, int line, string args) {
	cerr << "\033[0;31m\u001b[1mDEBUG\033[0m"
	     << " | "
	     << "\u001b[34m" << func << "\033[0m"
	     << ":"
	     << "\u001b[34m" << line << "\033[0m"
	     << " - "
	     << "[" << args << "] = ";
}

#ifdef LOCAL
#define dbg(args...) err_prefix(__FUNCTION__, __LINE__, #args), err(args)
#define dbgn(args...) err_prefix(__FUNCTION__, __LINE__, #args), errn(args)
#else
#define dbg(...)
#define dbgn(args...)
#endif

const auto beg_time = std::chrono::high_resolution_clock::now();
// https://stackoverflow.com/questions/47980498/accurate-c-c-clock-on-a-multi-core-processor-with-auto-overclock?noredirect=1&lq=1
double time_elapsed() {
	return chrono::duration<double>(std::chrono::high_resolution_clock::now() -
	                                beg_time)
	    .count();
}
}  // namespace Debug

inline namespace FileIO {
void setIn(str s) { freopen(s.c_str(), "r", stdin); }
void setOut(str s) { freopen(s.c_str(), "w", stdout); }
void setIO(str s = "") {
	cin.tie(0)->sync_with_stdio(0);  // unsync C / C++ I/O streams
	cout << fixed << setprecision(12);
	// cin.exceptions(cin.failbit);
	// throws exception when do smth illegal
	// ex. try to read letter into int
	if (sz(s)) setIn(s + ".in"), setOut(s + ".out");  // for old USACO
}
}  // namespace FileIO

/**
 * Description: shortest path
 * Source: own
 * Verification: https://open.kattis.com/problems/shortestpath1
 */

template <class C, bool directed> struct Dijkstra {
	int SZ;
	V<C> dist;
	V<V<pair<int, C>>> adj;
	void init(int _SZ) {
		SZ = _SZ;
		adj.clear();
		adj.rsz(SZ);
	}
	void ae(int u, int v, C cost) {
		adj.at(u).pb({v, cost});
		if (!directed) adj.at(v).pb({u, cost});
	}
	vi gen(int st) {
		dist.assign(SZ, numeric_limits<C>::max());
		using T = pair<C, int>;
		pqg<T> pq;
		auto ad = [&](int a, C b) {
			if (dist[a] <= b) return;
			pq.push({dist[a] = b, a});
		};
		ad(st, 0);
		vi seq;
		while (sz(pq)) {
			T x = pq.top();
			pq.pop();
			if (dist[x.s] < x.f) continue;
			seq.pb(x.s);
			each(y, adj[x.s]) ad(y.f, x.f + y.s);
		}
		assert(sz(seq) == SZ);
		return seq;
	}
};

Dijkstra<ll, false> Du, Dv, Ds;

int main() {
	// read read read
	setIO();
	def(int, N, M);
	def(int, s, t);
	def(int, u, v);
	--s, --t, --u, --v;
	Du.init(N), Dv.init(N), Ds.init(N);
	rep(M) {
		def(int, a, b, c);
		--a, --b;
		Du.ae(a, b, c);
		Dv.ae(a, b, c);
		Ds.ae(a, b, c);
	}
	Du.gen(u);
	Dv.gen(v);
	vi seq = Ds.gen(s);
	ll ans = Du.dist.at(v);
	V<AR<ll, 4>> dp(N, {BIG, BIG, BIG, BIG});
	dbg(seq);
	for (int x : seq) {
		if (x == seq.ft) dp.at(x).at(0) = 0;
		for (auto [y, w] : Ds.adj.at(x))
			if (w + Ds.dist.at(y) == Ds.dist.at(x)) {
				F0R(k, 4) ckmin(dp.at(x).at(k), dp.at(y).at(k));
			}
		F0R(k, 4) {
			if (k & 1)
				ckmin(dp.at(x).at(k), dp.at(x).at(k ^ 1) + Du.dist.at(x));
			if (k & 2)
				ckmin(dp.at(x).at(k), dp.at(x).at(k ^ 2) + Dv.dist.at(x));
		}
	}
	// dbg(dp.at(t));
	ps(min(ans, dp.at(t).at(3)));
	// you should actually read the stuff at the bottom
}

/* stuff you should look for
 * int overflow, array bounds
 * special cases (n=1?)
 * do smth instead of nothing and stay organized
 * WRITE STUFF DOWN
 * DON'T GET STUCK ON ONE APPROACH
 */

Compilation message (stderr)

commuter_pass.cpp: In function 'void FileIO::setIn(str)':
commuter_pass.cpp:246:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  246 | void setIn(str s) { freopen(s.c_str(), "r", stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp: In function 'void FileIO::setOut(str)':
commuter_pass.cpp:247:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  247 | void setOut(str s) { freopen(s.c_str(), "w", stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45