Submission #134998

#	Time	Username	Problem	Language	Result	Execution time	Memory
134998		qrno	Palindromes (APIO14_palindrome)	C++14	8 / 100	1087 ms	99384 KiB

palindrome

#include <iostream>
#include <string>
#include <cstring>
#include <map>
using namespace std;
 
map <string, int> M;
 
inline bool isPalindrome(string s) {
    for (int i = 0; i < s.size(); i++) {
        if (s[i] != s[s.size()-i-1])
            return false;
    }
    return true;
}

const int MAXN = 101010;

int n[MAXN];
int l[MAXN];

 
int main() {

    cin.tie(0);
    ios_base::sync_with_stdio(false);

    memset(l, -1, sizeof(l));
    memset(n, -1, sizeof(n));
 
    string a;
    cin >> a;

    for (int i = 0; i < a.size(); i++) {
        if (l[a[i]] != -1) {
            n[l[a[i]]] = i;
        }
        l[a[i]] = i;
    }

    int ans = 0;
 
    for (int i = 0; i < a.size(); i++) {
        for (int j = i; j != -1; j = n[j]) {
            string s = "";
            for (int m = i; m <= j; m++) {
                s += a[m];
            }
            if (isPalindrome(s)) {
                M[s]++;
                int m = s.size();
 
                ans = max(ans, m*M[s]);
            }
        }
    }
 
    cout << ans << '\n';
 
    return 0;
}

Compilation message (stderr)

palindrome.cpp: In function 'bool isPalindrome(std::__cxx11::string)':
palindrome.cpp:10:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < s.size(); i++) {
                     ~~^~~~~~~~~~
palindrome.cpp: In function 'int main()':
palindrome.cpp:34:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < a.size(); i++) {
                     ~~^~~~~~~~~~
palindrome.cpp:35:19: warning: array subscript has type 'char' [-Wchar-subscripts]
         if (l[a[i]] != -1) {
                   ^
palindrome.cpp:36:21: warning: array subscript has type 'char' [-Wchar-subscripts]
             n[l[a[i]]] = i;
                     ^
palindrome.cpp:38:15: warning: array subscript has type 'char' [-Wchar-subscripts]
         l[a[i]] = i;
               ^
palindrome.cpp:43:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < a.size(); i++) {
                     ~~^~~~~~~~~~

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