Submission #48003

#	Time	Username	Problem	Language	Result	Execution time	Memory
48003		E869120	Palindromes (APIO14_palindrome)	C++14	0 / 100	1092 ms	68348 KiB

palindrome

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

bool pal(string S) {
	string T = S; reverse(T.begin(), T.end());
	if (S == T) return true;
	return false;
}

string S; vector<long long>A; map<long long, int>M; int maxn = 0;
long long rem[100009], power[100009];

void init() {
	power[0] = 1; for (int i = 1; i < 100009; i++) power[i] = power[i - 1] * 31LL;
	for (int i = 1; i <= S.size(); i++) {
		rem[i] = rem[i - 1] * 31LL;
		rem[i] += (S[i - 1] - 'a');
	}
}
long long hash_value(long long l, long long r) {
	return rem[r] - rem[l] * power[r - l];
}

int main() {
	cin >> S; init();
	for (int i = 0; i < S.size(); i++) {
		int L = i, R = i;
		while (L >= 0 && R < S.size()) {
			if (S[L] != S[R]) break;
			long long J = hash_value(L, R + 1);
			M[J] += (R - L + 1); A.push_back(J);
			L--; R++;
		}
		L = i; R = i + 1;
		while (L >= 0 && R < S.size()) {
			if (S[L] != S[R]) break;
			long long J = hash_value(L, R + 1);
			M[J] += (R - L + 1); A.push_back(J);
			L--; R++;
		}
	}
	for (int i = 0; i < A.size(); i++) maxn = max(maxn, M[A[i]]);
	cout << maxn << endl;
	return 0;
}

Compilation message (stderr)

palindrome.cpp: In function 'void init()':
palindrome.cpp:19:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 1; i <= S.size(); i++) {
                  ~~^~~~~~~~~~~
palindrome.cpp: In function 'int main()':
palindrome.cpp:30:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < S.size(); i++) {
                  ~~^~~~~~~~~~
palindrome.cpp:32:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while (L >= 0 && R < S.size()) {
                    ~~^~~~~~~~~~
palindrome.cpp:39:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while (L >= 0 && R < S.size()) {
                    ~~^~~~~~~~~~
palindrome.cpp:46:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < A.size(); i++) maxn = max(maxn, M[A[i]]);
                  ~~^~~~~~~~~~

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