Submission #1040828

#	Time	Username	Problem	Language	Result	Execution time	Memory
1040828		anton	Cubeword (CEOI19_cubeword)	C++17	50 / 100	240 ms	24672 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 =16LL;
int nbP[MAX_N][MAX_N];
int mid[MAX_N][MAX_N][MAX_N][MAX_N];
int smid[MAX_N][MAX_N][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(0LL!=((1LL<<i)&b)){
            res = (res * pows[i])%MOD;
        }
    }

    return res;
}

unordered_map<int, int> inv;
int modinv(int a){
    if(inv.find(a)!=inv.end()){
        return inv[a];
    }
    int b= mexp(a, MOD-2);
    inv[a] = b;
    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;
            }
            int nb_same = 0;
            for(auto e: cur){
                if(e == first_v){
                    nb_same++;
                }
            }
            res.push_back({nbSteps * modinv(nb_same), cur});
        }
        

    }
    return res;
}

vector<pair<int, vector<int>>> all(int len, int base){
    vector<int> cur = vector<int>(len, 0);
    vector<pair<int, vector<int>>> res;

    bool ok = true;


    while(ok){
        cur.back()++;
        for(int i = len-1; i>0; i--){
            if(cur[i]>=base){
                cur[i-1]++;
                cur[i] = 0;
            }
        }

        if(cur[0] >=base){
            ok = false;
            cur[0] = 0;
        }
        res.push_back({1, cur});
    }
    return res;
}


vector<pair<int, vector<int>>> all_weighted(int len, int base){
    vector<int> cur = vector<int>(len, 0);
    vector<pair<int, vector<int>>> res;

    bool ok = true;


    while(ok){
        cur.back()++;
        for(int i = len-1; i>0; i--){
            if(cur[i]>=base){
                cur[i-1]++;
                cur[i] = 0;
            }
        }

        if(cur[0] >=base){
            ok = false;
            cur[0] = 0;
        }
        res.push_back({1, cur});
    }

    for(pair<int, vector<int>>& e: res){
        int oc= 1;
        for(int i = 0; i<4; i++){
            auto edge = cube_edges[i];
            oc =(oc * nbP[e.second[edge.first]][e.second[edge.second]])%MOD;
        }
        e.first = oc;
    }
    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);
        fill(&mid[0][0][0][0], &mid[MAX_N][0][0][0], 0);
        fill(&smid[0][0][0][0], &smid[MAX_N][0][0][0], 0);


        for(auto e: words[len]){
            int a=  e[0]-'a';
            int b= e.back()-'a';
            nbP[a][b]++;
        }
        vector<pair<int, vector<int>>> colorings=  all_weighted(4,MAX_N);


        for(auto e: colorings){
            /*cout<<"starting from "<<endl;
            for(auto c: e.second){
                cout<<c<<" ";
            }
            cout<<endl;*/
            int i= 0;
            for(int i = 0; i<MAX_N; i++){
                smid[i][e.second[1]][e.second[2]][e.second[3]] =(smid[i][e.second[1]][e.second[2]][e.second[3]] + (nbP[e.second[0]][i] * e.first)%MOD)%MOD;
            }
            
        }

        for(auto e: colorings){
            auto v=  e.second;

            for(int i = 0; i<MAX_N; i++){
                mid[v[0]][i][v[2]][v[3]] =(mid[v[0]][i][v[2]][v[3]]  + (nbP[v[1]][i] * smid[v[0]][v[1]][v[2]][v[3]])%MOD)%MOD;
            }
        }


        for(auto e: colorings){
            auto v = e.second;
            RES = (RES + (mid[v[0]][v[1]][v[2]][v[3]] * mid[v[3]][v[2]][v[1]][v[0]])%MOD)%MOD;
        }
    }

    cout<<RES<<endl;
}

Compilation message (stderr)

cubeword.cpp: In function 'bool is_palindrome(std::string)':
cubeword.cpp:32:21: 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]
   32 |     for(int i = 0; i<(s.size()+1)/2; i++){
      |                    ~^~~~~~~~~~~~~~~
cubeword.cpp: In function 'int main()':
cubeword.cpp:204:17: warning: unused variable 'i' [-Wunused-variable]
  204 |             int i= 0;
      |                 ^

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