Submission #563049

#	Time	Username	Problem	Language	Result	Execution time	Memory
563049		SanguineChameleon	Palindromic Partitions (CEOI17_palindromic)	C++14	100 / 100	164 ms	28492 KiB

palindromic

// BEGIN BOILERPLATE CODE

#include <bits/stdc++.h>
using namespace std;

#ifdef KAMIRULEZ
	const bool kami_loc = true;
	const long long kami_seed = 69420;
#else
	const bool kami_loc = false;
	const long long kami_seed = chrono::steady_clock::now().time_since_epoch().count();
#endif

const string kami_fi = "kamirulez.inp";
const string kami_fo = "kamirulez.out";
mt19937_64 kami_gen(kami_seed);

long long rand_range(long long rmin, long long rmax) {
	uniform_int_distribution<long long> rdist(rmin, rmax);
	return rdist(kami_gen);
}

void file_io(string fi, string fo) {
	if (fi != "" && (!kami_loc || fi == kami_fi)) {
		freopen(fi.c_str(), "r", stdin);
	}
	if (fo != "" && (!kami_loc || fo == kami_fo)) {
		freopen(fo.c_str(), "w", stdout);
	}
}

void set_up() {
	if (kami_loc) {
		file_io(kami_fi, kami_fo);
	}
	ios_base::sync_with_stdio(0);
	cin.tie(0);
}

void just_do_it();

void just_exec_it() {
	if (kami_loc) {
		auto pstart = chrono::steady_clock::now();
		just_do_it();
		auto pend = chrono::steady_clock::now();
		long long ptime = chrono::duration_cast<chrono::milliseconds>(pend - pstart).count();
		string bar(50, '=');
		cout << '\n' << bar << '\n';
		cout << "Time: " << ptime << " ms" << '\n';
	}
	else {
		just_do_it();
	}
}

int main() {
	set_up();
	just_exec_it();
	return 0;
}

// END BOILERPLATE CODE

// BEGIN MAIN CODE

const int ms = 2e6 + 20;
int a[ms];
int p[ms];

void query() {
	string s;
	cin >> s;
	int n = s.size();
	int sz = n / 2 * 2 * 2 + 1;
	int lt = 0;
	int rt = n - 1;
	for (int i = 0; i < sz; i++) {
		if (i % 2 == 0) {
			a[i] = -1;
		}
		else {
			if ((i / 2) % 2 == 0) {
				a[i] = s[lt] - 'a';
				lt++;
			}
			else {
				a[i] = s[rt] - 'a';
				rt--;
			}
		}
	}
	if (n % 2 == 1) {
		a[sz++] = -1;
	}
	int lx = 1;
	lt = 0;
	rt = 0;
	int res = 0;
	for (int i = 0; i < sz; i++) {
		p[i] = max(0, min(rt - i, p[lt + rt - i]));
		while (i - p[i] >= 0 && i + p[i] < sz && a[i - p[i]] == a[i + p[i]]) {
			p[i]++;
		}
		if (i + p[i] > rt) {
			lt = i - p[i];
			rt = i + p[i];
		}
		if (i % 2 == 0) {
			if (i - p[i] + 1 <= lx && i > lx) {
				res += 2;
				lx = i + i - lx + 2;
			}
		}

	}
	if (lx < sz) {
		res++;
	}
	cout << res << '\n';
}

void just_do_it() {
	int t;
	cin >> t;
	for (int i = 0; i < t; i++) {
		query();
	}
}

// END MAIN CODE

Compilation message (stderr)

palindromic.cpp: In function 'void file_io(std::string, std::string)':
palindromic.cpp:25:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 |   freopen(fi.c_str(), "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
palindromic.cpp:28:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |   freopen(fo.c_str(), "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 40 / 40