답안 #879410

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
879410	2023-11-27T10:27:23 Z	marvinthang	회문 (APIO14_palindrome)	C++17	100 / 100	292 ms	71520 KB

palindrome

/*************************************
*    author: marvinthang             *
*    created: 27.11.2023 15:58:18    *
*************************************/

#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 << '}'; }
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 BASE = 31;

void process(void) {
	string s; cin >> s;

	auto manacher_odd = [&] (string s) {
		int n = s.size();
		s = '$' + s + '^';
		vector <int> p(n + 1);
		int l = 1, r = 1;
		FORE(i, 1, n) {
			p[i] = max(0, min(r - i, p[l + r - i]));
			while (s[i - p[i]] == s[i + p[i]]) ++p[i];
			if (i + p[i] > r) r = i + p[i], l = i - p[i];
		}
		return vector(1 + ALL(p));
	};
	auto manacher = [&] (string s) {
		string t;
		for (char c: s) t += string("#") + c;
		auto res = manacher_odd(t + "#");
		for (int &x: res) x >>= 1;
		return vector(1 + ALL(res) - 1);
	};
	auto pl = manacher(s);
	s = s + '#';
	int n = s.size();
	vector <int> pos(n), cnt(n), lcp(n);
	iota(ALL(pos), 0);
	sort(ALL(pos), [&] (int a, int b) { return s[a] < s[b]; });
	cnt[pos[0]] = 0;
	FOR(i, 1, n) cnt[pos[i]] = cnt[pos[i - 1]] + (s[pos[i]] != s[pos[i - 1]]);
	auto countSort = [&] (vector <int> &p, vector <int> &c) {
		vector <int> pos(n), new_p(n);
		for (int &x: c) if (x + 1 < n) ++pos[x + 1];
		partial_sum(ALL(pos), pos.begin());
		for (int &x: p) new_p[pos[c[x]]++] = x;
		p = move(new_p);
	};
	for (int k = 1; k < n; k <<= 1) {
		REP(i, n) {
			pos[i] = pos[i] - k;
			if (pos[i] < 0) pos[i] += n;
		}
		countSort(pos, cnt);
		vector <int> new_c(n);
		new_c[pos[0]] = 0;
		pair <int, int> prv(cnt[pos[0]], cnt[pos[0] + k - (pos[0] + k < n ? 0 : n)]);
		FOR(i, 1, n) {
			pair <int, int> cur(cnt[pos[i]], cnt[pos[i] + k - (pos[i] + k < n ? 0 : n)]);
			new_c[pos[i]] = new_c[pos[i - 1]] + (prv != cur);
			prv = cur;
		}
		cnt = move(new_c);
	}
	for (int i = 0, k = 0; i < n - 1; ++i) {
		int j = pos[cnt[i] - 1];
		while (s[i + k] == s[j + k]) ++k;
		lcp[cnt[i]] = k;
		k = max(k - 1, 0);
	}
	vector <vector <int>> add_odd(n), add_even(n), del_odd(n), del_even(n);
	REP(i, pl.size()) if (pl[i]) {
		int p = i / 2;
		if (i & 1) {
			add_even[p - pl[i] + 1].push_back(p);
			del_even[p + pl[i]].push_back(p);
		} else {
			add_odd[p - pl[i] + 1].push_back(p);
			del_odd[p + pl[i] - 1].push_back(p);
		}
	}
	set <int> ms_odd, ms_even;
	vector <int> max_palin(n, 0);
	REP(i, n - 1) {
		for (int x: add_odd[i]) ms_odd.insert(x);
		for (int x: add_even[i]) ms_even.insert(x);
		int upper = lcp[cnt[i]];
		if (upper + 2 * i - 1 >= 0) {
			auto it = ms_odd.upper_bound((upper + 2 * i - 1) / 2);
			if (it != ms_odd.begin()) maximize(max_palin[i], (*prev(it) - i) * 2 + 1);
		}
		if (upper + 2 * i - 2 >= 0) {
			auto it = ms_even.upper_bound((upper + 2 * i - 2) / 2);
			if (it != ms_even.begin()) maximize(max_palin[i], (*prev(it) - i + 1) * 2);
		}
		for (int x: del_odd[i]) ms_odd.erase(x);
		for (int x: del_even[i]) ms_even.erase(x);
	}
	stack <int> st;
	vector <int> left(n);
	REP(i, n) {
		while (!st.empty() && lcp[st.top()] >= lcp[i]) st.pop();
		left[i] = st.empty() ? 0 : st.top();
		st.push(i);
	}
	while (!st.empty()) st.pop();
	long long res = 0;
	REP(i, pl.size()) maximize(res, pl[i] * 2 - !(i & 1));
	REPD(i, n) {
		while (!st.empty() && lcp[st.top()] >= lcp[i]) st.pop();
		maximize(res, 1LL * ((st.empty() ? n : st.top()) - left[i]) * max_palin[pos[i]]);
		st.push(i);
	}
	cout << res << '\n';
}

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

Compilation message

palindrome.cpp: In function 'int main()':
palindrome.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); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
palindrome.cpp:156:2: note: in expansion of macro 'file'
  156 |  file("palindrome");
      |  ^~~~
palindrome.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); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
palindrome.cpp:156:2: note: in expansion of macro 'file'
  156 |  file("palindrome");
      |  ^~~~

Subtask #1

8.0 / 8.0

#	결과	실행 시간	메모리	Grader output
1	Correct	1 ms	348 KB	Output is correct
2	Correct	0 ms	348 KB	Output is correct
3	Correct	0 ms	348 KB	Output is correct
4	Correct	0 ms	348 KB	Output is correct
5	Correct	0 ms	344 KB	Output is correct
6	Correct	0 ms	348 KB	Output is correct
7	Correct	0 ms	348 KB	Output is correct
8	Correct	0 ms	348 KB	Output is correct
9	Correct	0 ms	348 KB	Output is correct
10	Correct	0 ms	348 KB	Output is correct
11	Correct	0 ms	348 KB	Output is correct
12	Correct	0 ms	348 KB	Output is correct
13	Correct	0 ms	348 KB	Output is correct
14	Correct	0 ms	348 KB	Output is correct
15	Correct	0 ms	348 KB	Output is correct
16	Correct	0 ms	348 KB	Output is correct
17	Correct	0 ms	348 KB	Output is correct
18	Correct	0 ms	348 KB	Output is correct
19	Correct	1 ms	348 KB	Output is correct
20	Correct	0 ms	348 KB	Output is correct
21	Correct	0 ms	348 KB	Output is correct
22	Correct	0 ms	348 KB	Output is correct
23	Correct	1 ms	348 KB	Output is correct
24	Correct	0 ms	348 KB	Output is correct
25	Correct	0 ms	600 KB	Output is correct
26	Correct	0 ms	348 KB	Output is correct
27	Correct	0 ms	348 KB	Output is correct
28	Correct	0 ms	348 KB	Output is correct
29	Correct	0 ms	348 KB	Output is correct
30	Correct	0 ms	348 KB	Output is correct
31	Correct	0 ms	348 KB	Output is correct
32	Correct	0 ms	348 KB	Output is correct

Subtask #2

15.0 / 15.0

#	결과	실행 시간	메모리	Grader output
1	Correct	1 ms	604 KB	Output is correct
2	Correct	1 ms	604 KB	Output is correct
3	Correct	1 ms	604 KB	Output is correct
4	Correct	1 ms	604 KB	Output is correct
5	Correct	1 ms	604 KB	Output is correct
6	Correct	1 ms	604 KB	Output is correct
7	Correct	1 ms	604 KB	Output is correct
8	Correct	1 ms	604 KB	Output is correct
9	Correct	1 ms	604 KB	Output is correct
10	Correct	1 ms	604 KB	Output is correct
11	Correct	1 ms	604 KB	Output is correct
12	Correct	1 ms	604 KB	Output is correct

Subtask #3

24.0 / 24.0

#	결과	실행 시간	메모리	Grader output
1	Correct	4 ms	2108 KB	Output is correct
2	Correct	4 ms	2124 KB	Output is correct
3	Correct	7 ms	2636 KB	Output is correct
4	Correct	6 ms	2636 KB	Output is correct
5	Correct	4 ms	1868 KB	Output is correct
6	Correct	4 ms	2112 KB	Output is correct
7	Correct	4 ms	2112 KB	Output is correct
8	Correct	4 ms	2112 KB	Output is correct
9	Correct	4 ms	2112 KB	Output is correct
10	Correct	4 ms	2368 KB	Output is correct

Subtask #4

26.0 / 26.0

#	결과	실행 시간	메모리	Grader output
1	Correct	56 ms	18232 KB	Output is correct
2	Correct	54 ms	17328 KB	Output is correct
3	Correct	86 ms	24000 KB	Output is correct
4	Correct	77 ms	22404 KB	Output is correct
5	Correct	44 ms	15896 KB	Output is correct
6	Correct	52 ms	16044 KB	Output is correct
7	Correct	54 ms	18372 KB	Output is correct
8	Correct	46 ms	18880 KB	Output is correct
9	Correct	51 ms	19916 KB	Output is correct
10	Correct	55 ms	19360 KB	Output is correct

Subtask #5

27.0 / 27.0

#	결과	실행 시간	메모리	Grader output
1	Correct	188 ms	53896 KB	Output is correct
2	Correct	147 ms	48812 KB	Output is correct
3	Correct	292 ms	71520 KB	Output is correct
4	Correct	239 ms	62528 KB	Output is correct
5	Correct	146 ms	47172 KB	Output is correct
6	Correct	163 ms	52908 KB	Output is correct
7	Correct	173 ms	53092 KB	Output is correct
8	Correct	152 ms	56108 KB	Output is correct
9	Correct	154 ms	56092 KB	Output is correct
10	Correct	200 ms	57764 KB	Output is correct
11	Correct	177 ms	54440 KB	Output is correct
12	Correct	158 ms	57008 KB	Output is correct