Submission #735920

#	Time	Username	Problem	Language	Result	Execution time	Memory
735920		marvinthang	Building 4 (JOI20_building4)	C++17	100 / 100	236 ms	45520 KiB

building4

/*************************************
*    author: marvinthang             *
*    created: 03.05.2023 17:09:59    *
*************************************/

#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--; )
#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 << '}'; }
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 MAX = 1e6 + 6;
const int INF = 1e9;

int N, A[MAX][2];

void init(void) {
	cin >> N;
	REP(t, 2) REP(i, 2 * N) cin >> A[i][t];
}

int ma[MAX][2], mi[MAX][2];

void process(void) {
	memset(ma, 0xc3, sizeof(ma));
	memset(mi, 0x3f, sizeof(ma));
	mi[1][0] = ma[1][0] = 0;
	mi[1][1] = ma[1][1] = 1;
	FOR(i, 1, 2 * N) REP(k, 2) {
		REP(l, 2) if (A[i - 1][k] <= A[i][l]) {
			maximize(ma[i + 1][l], ma[i][k] + l);
			minimize(mi[i + 1][l], mi[i][k] + l);
		}
	}
	int t = mi[2 * N][1] <= N && N <= ma[2 * N][1];
	if (mi[2 * N][t] > N || ma[2 * N][t] < N) return void(cout << "-1\n");
	string res(1, 'A' + t);
	int rem = N;
	FORD(i, 2 * N, 1) {
		rem -= t;
		REP(k, 2) if (A[i - 1][k] <= A[i][t] && mi[i][k] <= rem && rem <= ma[i][k]) {
			t = k;
			break;
		}
		res += char('A' + t);
	}
	reverse(ALL(res));
	cout << res << '\n';
}

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

Compilation message (stderr)

building4.cpp: In function 'int main()':
building4.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); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
building4.cpp:88:2: note: in expansion of macro 'file'
   88 |  file("C");
      |  ^~~~
building4.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); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
building4.cpp:88:2: note: in expansion of macro 'file'
   88 |  file("C");
      |  ^~~~

• Subtask 1: 11 / 11
• Subtask 2: 89 / 89