Submission #884348

#	Time	Username	Problem	Language	Result	Execution time	Memory
884348		marvinthang	Collecting Stamps 3 (JOI20_ho_t3)	C++17	100 / 100	420 ms	453368 KiB

ho_t3

/*************************************
*    author: marvinthang             *
*    created: 07.12.2023 15:03:09    *
*************************************/

#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i-- > 0; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
// copied from https://codeforces.com/blog/entry/76149
template<typename T, int D> struct Vec: public vector <Vec <T, D - 1>> {
    static_assert(D >= 1, "Vector dimension must be greater than zero!");
    template <typename... Args>
    Vec(int n = 0, Args... args): vector <Vec <T, D - 1>>(n, Vec <T, D - 1>(args...)) {}
};
template<typename T> struct Vec <T, 1>: public vector <T> {
    Vec(int n = 0, const T& val = T()): vector <T>(n, val) {}
};
template <class A, class B> bool minimize(A &a, B b)  { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b)  { if (a < b) { a = b; return true; } return false; }

// end of template

const int INF = 1e9 + 7;

void process(void) {
	int n, l; cin >> n >> l;
	vector <int> x(n + 1), t(n + 1);
	REP(i, n) cin >> x[i + 1];
	REP(i, n) cin >> t[i + 1];
	Vec<int, 4> dp(n + 2, n + 2, n + 1, 2, INF);
	auto dist = [&] (int a, int b) {
		return min(abs(x[a] - x[b]), l - abs(x[a] - x[b]));
	};
	dp[0][n + 1][0][0] = 0;
	int res = 0;
	REP(l, n + 1) FORD(r, n + 2, l + 1) REP(cnt, n + 1) REP(p, 2) if (dp[l][r][cnt][p] < INF) {
		res = max(res, cnt);
		int cur = p ? r : l;
		if (l + 1 < r) {
			int v = dp[l][r][cnt][p] + dist(cur, l + 1);
			minimize(dp[l + 1][r][cnt + (v <= t[l + 1])][0], v);
			v = dp[l][r][cnt][p] + dist(cur, r - 1);
			minimize(dp[l][r - 1][cnt + (v <= t[r - 1])][1], v);
		}
	}
	cout << res << '\n';
}

int main(void) {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); // cout.tie(nullptr);
	file("JOI20_ho_t3");
	// int t; cin >> t; while (t--)
	process();
	// cerr << "Time elapsed: " << TIME << " s.\n";
	return (0^0);
}

Compilation message (stderr)

ho_t3.cpp: In function 'int main()':
ho_t3.cpp:30:61: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
ho_t3.cpp:84:2: note: in expansion of macro 'file'
   84 |  file("JOI20_ho_t3");
      |  ^~~~
ho_t3.cpp:30:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
ho_t3.cpp:84:2: note: in expansion of macro 'file'
   84 |  file("JOI20_ho_t3");
      |  ^~~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 75 / 75