Submission #858406

#	Time	Username	Problem	Language	Result	Execution time	Memory
858406		Tenis0206	Palindromic Partitions (CEOI17_palindromic)	C++11	100 / 100	117 ms	20864 KiB

palindromic

#include <bits/stdc++.h>

using namespace std;

const int nmax = 1e6;
const int b = 27;
const int Mod = 1e9 + 7;

string s;

int h[nmax + 5];
int put[nmax + 5];

int get_hash(int st, int dr)
{
    return (h[dr] - 1LL * h[st - 1] * put[dr - st + 1] % Mod + Mod) % Mod;
}

int solve(int st, int dr)
{
    if(st > dr)
    {
        return 0;
    }
    for(int len=1;st + len - 1 < dr - len + 1;len++)
    {
        bool ok = (get_hash(st,st+len-1) == get_hash(dr-len+1,dr));
        if(ok)
        {
            return 2 + solve(st + len, dr - len);
        }
    }
    return 1;
}

void solve_test()
{
    cin>>s;
    s = "#" + s;
    put[0] = 1;
    for(int i=1;i<s.size();i++)
    {
        put[i] = 1LL * put[i - 1] * b % Mod;
        h[i] = (1LL * h[i - 1] * b + s[i] - 'a' + 1) % Mod;
    }
    cout<<solve(1,s.size() - 1)<<'\n';
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    #ifdef home
    freopen("nr.in","r",stdin);
    freopen("nr.out","w",stdout);
    #endif // home
    int t;
    cin>>t;
    for(int test=1;test<=t;test++)
    {
        solve_test();
    }
    return 0;
}

Compilation message (stderr)

palindromic.cpp: In function 'void solve_test()':
palindromic.cpp:41:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |     for(int i=1;i<s.size();i++)
      |                 ~^~~~~~~~~

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