Submission #961184

#	Time	Username	Problem	Language	Result	Execution time	Memory
961184		LucaIlie	Palindromic Partitions (CEOI17_palindromic)	C++17	100 / 100	524 ms	26620 KiB

palindromic

#include <bits/stdc++.h>

using namespace std;

struct hasher {
    int mod, b;
    vector<int> hashh, put;

    hasher( string s, int _mod, int _b ) {
        mod = _mod;
        b = _b;

        hashh.resize( s.size() + 1 );
        put.resize( s.size() + 1 );

        put[0] = 1;
        hashh[0] = 0;
        for ( int i = 1; i <= s.size(); i++ ) {
            put[i] = (long long)put[i - 1] * b % mod;
            hashh[i] = ((long long)hashh[i - 1] * b + s[i - 1] - 'a') % mod;
        }
    }

    int getHash( int l, int r ) {
        return (hashh[r + 1] - (long long)hashh[l] * put[r - l + 1] % mod + mod) % mod;
    }
};

const int mod1 = 1e9 + 7;
const int mod2 = 1e9 + 9;
const int b1 = 37;
const int b2 = 31;

int main() {
    int t;

    cin >> t;
    while ( t-- ) {
        string s;

        cin >> s;
        hasher hash1( s, mod1, b1 );
        hasher hash2( s, mod2, b2 );

        int l = 0, r = s.size() - 1, cuv = 0;
        while ( l <= r ) {
            int i = 1;
            while ( i <= (r - l + 1) / 2 ) {
                if ( hash1.getHash( l, l + i - 1 ) == hash1.getHash( r - i + 1, r ) && hash2.getHash( l, l + i - 1 ) == hash2.getHash( r - i + 1, r ) )
                    break;
                i++;
            }
            if ( i <= (r - l + 1) / 2 ) {
                l += i;
                r -= i;
                cuv += 2;
            } else {
                cuv++;
                break;
            }
        }

        cout << cuv << "\n";
    }

    return 0;
}

Compilation message (stderr)

palindromic.cpp: In constructor 'hasher::hasher(std::string, int, int)':
palindromic.cpp:18:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 |         for ( int i = 1; i <= s.size(); i++ ) {
      |                          ~~^~~~~~~~~~~

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