Submission #346538

#	Time	Username	Problem	Language	Result	Execution time	Memory
346538		aritra741	Palindromes (APIO14_palindrome)	C++14	100 / 100	40 ms	40968 KiB

palindrome

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


const int MAXN = 300007;
const int N = 26;

long long ans;

struct Palindromic_Tree
{
	int next[MAXN][N];
	int fail[MAXN];
	long long cnt[MAXN]; // কতবার palindromic sub-string টি মুল string এর মধ্যে

	int num[MAXN]; //many palindromic sub-string ends in that position
	int start[MAXN];
	int end[MAXN];
	int len[MAXN];
	int S[MAXN];
	int last;
	int n;
	int p; // total node(number of unique palindrom in string)


	int newnode(int l)
	{
		for (int i = 0; i < N; i++) next[p][i] = 0;
		cnt[p] = 0;
		num[p] = 0;
		len[p] = l;
		return p++;
	}

	void init()
	{
		p = 0;
		newnode(0);
		newnode(-1);
		last = 0;
		n = 0;
		S[n] = -1;
		fail[0] = 1;
	}

	int get_fail(int x) { // KMP
		while (S[n - len[x] - 1] != S[n]) x = fail[x];
		return x;
	}

	void add(int c, int i)
	{
		c -= 'a';
		S[++n] = c;

		int cur = get_fail(last);

		if (!next[cur][c]) {
			int now = newnode(len[cur] + 2);
			end[now] = i;
			start[now] = i - len[cur] - 2 + 1;
			fail[now] = next[get_fail(fail[cur])][c];
			next[cur][c] = now;
			num[now] = num[fail[now]] + 1;
		}
		last = next[cur][c];
		cnt[last]++;
	}

	void count()
	{
		for (int i = p - 1; i >= 0; --i) cnt[fail[i]] += cnt[i];
	}

	void print()
	{
		for (int i = 1; i <= p - 2; i++)
		{
			printf("%c ", S[i] + 'a');
		}
		printf("\n");

		for (int i = 2; i < p; i++)
		{
			printf("%lld ", cnt[i]);
		}
		printf("\n");
		for (int i = 2; i < p; i++)
		{
			printf("%d ", num[i]);
		}
		printf("\n");
		for (int i = 2; i < p; i++)
		{
			printf("%d ", start[i]);
		}
		printf("\n");
		for (int i = 2; i < p; i++)
		{
			printf("%d ", end[i]);
		}
		printf("\n");
	}
} tt;


int main()
{
	string str;

	cin >> str;

	tt.init();

	for (int i = 0; i < str.size(); i++)
	{
		tt.add(str[i], i);
	}

	tt.count();

	for( int i=0;i<tt.p;i++ )
		ans = max( ans, tt.cnt[i] * tt.len[i] ); 

	printf("%lld\n", ans);
}

Compilation message (stderr)

palindrome.cpp: In function 'int main()':
palindrome.cpp:115:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  115 |  for (int i = 0; i < str.size(); i++)
      |                  ~~^~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 26 / 26
• Subtask 5: 27 / 27