Submission #48019

#	Time	Username	Problem	Language	Result	Execution time	Memory
48019		E869120	Palindromes (APIO14_palindrome)	C++14	32 / 100	1083 ms	11800 KiB

palindrome

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

string S; int L[100009], N, col[100009], cnts; vector<int>x[100009], y[100009];

long long Get(int pos) {
	if (pos < 0) return -1;
	if (pos >= N) return -2;
	return L[pos];
}

int main() {
	cin >> S; N = S.size(); if (S.size() == 1) { cout << "1" << endl; return 0; }
	for (int i = 0; i < N; i++) L[i] = (S[i] - 'a');
	for (int i = 0; i < N; i++) x[0].push_back(i);

	long long maxn = 0; cnts = 1;

	for (int i = 0; i <= N / 2 + 1; i++) {
		int cnt = 0;
		for (int j = 0; j < cnts; j++) {
			if (x[j].size() == 1) { int to = x[j][0]; if (Get(to - i) == Get(to + i)) { y[cnt] = x[j]; cnt++; } continue; }
			
			vector<int>H[26];
			for (int k = 0; k < x[j].size(); k++) {
				int to = x[j][k];
				if (Get(to - i) != Get(to + i)) continue;
				H[Get(to + i)].emplace_back(to);
			}
			for (int k = 0; k < 26; k++) {
				if (H[k].size() >= 1) { y[cnt] = H[k]; cnt++; }
			}
		}
		for (int j = 0; j < cnt; j++) { x[j] = y[j]; maxn = max(maxn, 1LL * (long long)x[j].size()*(i * 2 + 1)); } cnts = cnt;
	}

	for (int i = 0; i < 100009; i++) x[i].clear(); cnts = 1;
	for (int i = 0; i < N; i++) x[0].push_back(i);

	for (int i = 0; i <= N / 2 + 1; i++) {
		int cnt = 0;
		for (int j = 0; j < cnts; j++) {
			if (x[j].size() == 1) { int to = x[j][0]; if (Get(to - i) == Get(to + i)) { y[cnt] = x[j]; cnt++; } continue; }

			vector<int>H[26];
			for (int k = 0; k < x[j].size(); k++) {
				int to = x[j][k];
				if (Get(to - i) != Get(to + i + 1)) continue;
				H[Get(to + i)].emplace_back(to);
			}
			for (int k = 0; k < 26; k++) {
				if (H[k].size() >= 1) { y[cnt] = H[k]; cnt++; }
			}
		}
		for (int j = 0; j < cnt; j++) { x[j] = y[j]; maxn = max(maxn, 1LL * (long long)x[j].size()*(i * 2 + 2)); }
		cnts = cnt;
	}
	cout << maxn << endl;
	return 0;
}

Compilation message (stderr)

palindrome.cpp: In function 'int main()':
palindrome.cpp:28:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int k = 0; k < x[j].size(); k++) {
                    ~~^~~~~~~~~~~~~
palindrome.cpp:40:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for (int i = 0; i < 100009; i++) x[i].clear(); cnts = 1;
  ^~~
palindrome.cpp:40:49: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  for (int i = 0; i < 100009; i++) x[i].clear(); cnts = 1;
                                                 ^~~~
palindrome.cpp:49:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int k = 0; k < x[j].size(); k++) {
                    ~~^~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 0 / 15
• Subtask 3: 24 / 24
• Subtask 4: 0 / 26
• Subtask 5: 0 / 27