Submission #1040527

#	Time	Username	Problem	Language	Result	Execution time	Memory
1040527		anton	Cubeword (CEOI19_cubeword)	C++17	0 / 100	373 ms	57000 KiB

cubeword

#include<bits/stdc++.h>

using namespace std;
#define int long long
#define pii pair<int, int>

const int MOD = 998244353LL;
const int MAX_N = 40LL;
int nbP[MAX_N][MAX_N];
int RES = 0;

vector<pii> cube_edges = {
{0, 1},
{1, 2},
{2, 3},
{3, 0},
{4, 5},
{5, 6},
{6, 7},
{7, 4},
{0, 4},
{1, 5}, 
{2, 6},
{3, 7},
};


bool is_palindrome(string s){
    bool ok = true;
    for(int i = 0; i<(s.size()+1)/2; i++){
        ok &= (s[i] == s[s.size()-i-1]);
    }
    return ok;
}

int mexp(int a, int b){
    int res = 1;
    vector<int>pows(1, a);


    for(int i= 1; i<35; i++){
        pows.push_back((pows.back()*pows.back())%MOD);
    }
    
    for(int i = 0; i<35; i++){
        if(0!=((1LL<<i)&b)){
            res = (res * pows[i])%MOD;
        }
    }

    return res;
}
int modinv(int a){
    int b= mexp(a, MOD-2);
    assert((a*b)%MOD == 1);
    return b;
}
vector<pair<int, vector<int>>> iterate_all(int nbSteps, int maxC){
    vector<int> cur = vector<int>(nbSteps, 0);
    vector<pair<int, vector<int>>> res;

    bool ok = true;

    for(int first_v = 0; first_v <maxC; first_v++){
        cur =vector<int>(nbSteps, 0);
        cur[0] = first_v;
        ok =true;
        while(ok){
            cur.back()++;
            for(int i = nbSteps-1; i>1; i--){
                if(cur[i]>first_v){
                    cur[i-1]++;
                    cur[i] = 0;
                }
            }

            if(cur[1] >first_v){
                ok = false;
                cur[1] = 0;
            }
            else{
                int nb_same = 0;
                for(auto e: cur){
                    if(e == first_v){
                        nb_same++;
                    }
                }
                res.push_back({nbSteps * modinv(nb_same), cur});
            }
        }
        

    }
    return res;
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int N;
    cin>>N;
    vector<set<string>> words(11);

    for(int i = 0; i<N; i++){
        string s;
        cin>>s;
        if(is_palindrome(s)){
            words[s.size()].insert(s);
        }
        else{
            words[s.size()].insert(s);
            reverse(s.begin(), s.end());
            words[s.size()].insert(s);
        }
    }

    vector<pair<int, vector<int>>> colorings=  iterate_all(8, 6);

    for(int len = 3; len<=10; len++){
        fill(&nbP[0][0], &nbP[MAX_N][0], 0);


        for(auto e: words[len]){
            int a=  e[0]-'a';
            int b= e.back()-'a';
            nbP[a][b]++;
        }

        for(auto list: colorings){
            int nb_cur = 1;
            for(auto edge: cube_edges){
                nb_cur = (nb_cur * nbP[list.second[edge.first]][list.second[edge.second]])%MOD;
            }
            nb_cur = (nb_cur * list.first)%MOD;
            RES = (RES + nb_cur)%MOD;
        }
    }

    cout<<RES<<endl;
}

Compilation message (stderr)

cubeword.cpp: In function 'bool is_palindrome(std::string)':
cubeword.cpp:30:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for(int i = 0; i<(s.size()+1)/2; i++){
      |                    ~^~~~~~~~~~~~~~~

• Subtask 1: 0 / 21
• Subtask 2: 0 / 29
• Subtask 3: 0 / 34
• Subtask 4: 0 / 16